Automatic cell identification and enrichment in lung cancer. I. Light scatter and fluorescence parameters

Cell-Specific and Nuclear Targeting with [M(CO)3]+ (M=99mTc, Re)-Based Complexes Conjugated to Acridine Orange and Bombesin

Receptor-specific nuclear targeting requires trifunctional metal complexes. We have synthesized [M(L(2)-pept)(L(1)-acr)(CO)(3)] (pept=peptide; acr=acridine-based agent) in which the fac-[M(CO)(3)](+) moiety (1st function, M=(99m)Tc, Re) couples an acridine-based nuclear-targeting agent (2nd function, L(1)-acr) and the specific cell-receptor-binding peptide bombesin (3rd function, L(2)-pept). The metal-mediated coupling is based on the mixed ligand [2+1] principle. The nuclear targeting agents have been derivatised with an isocyanide group for monodentate (L(1)) and bombesin (BBN) with a bidentate ligand (L(2)) for complexation to fac-[M(CO)(3)](+). For nuclear uptake studies, the model complexes [Re(L(2))(L(1)-acr)(CO)(3)] (L(2)=pyridine-2-carboxylic acid and pyridine-2,4-dicarboxylic acid) were synthesized and structurally characterized. We selected acridine derivatives as nuclear-targeting agents, because they are very good nucleus-staining agents and exhibit strong fluorescence. Despite the bulky metal complexes attached to acridine, all [Re(L(2))(L(1)-acr)(CO)(3)] showed high accumulation in the nuclei of PC3 and B16F1 cells, as evidenced by fluorescence microscopy. For radiopharmaceutical purposes, the (99m)Tc analogues have been prepared and radioactivity distribution confirmed the fluorescence results. Coupling of BBN to L(2) gave the receptor-selective complexes [M(L(2)-BBN)(L(1)-acr)(CO)(3)]. Whereas no internalization was found with B16F1 cells, fluorescence microscopy on PC3 cells bearing the BBN receptor showed high and rapid uptake by receptor-mediated endocytosis into the cytoplasm, but not into the nucleus.

Strategies for automated placement of cells for microscopy

Computer-software-controlled placement of cells onto microscope slides is advantageous for quantitative optical microscopy. Cell detection, indentification, and placement have been implemented on a software-controlled flow sorter. Computer hardware timing latencies that comprise the dead times of the system are sufficiently short (10 micros) to allow adequate dealy of cells for sorting. Operating system timing latencies (150 micros) are also short enough for low-rate sorting. As a result of the low cost of computers and because formats for cell placement are still controversial, software control is desirable somce it provides the flexibility to implement multiple variations for cell detection, identification, amd sorting.

Automatic cell identification and enrichment in lung cancer: V. Adenocarcinoma and large cell undifferentiated carcinoma

The aims of this study were to develop a protocol for the identification and enrichment of cancer cells from sputum obtained from patients with adenocarcinoma of the lung (n = 6) and large-cell undifferentiated carcinoma of the lung (n = 2), and to compare these findings with the results from our previous studies on other cell types from lung cancer. The hypotheses tested were: Cancer cells in sputum can be preserved following flow sorting. Enrichment for cancer cells from acridine orange (AO)-stained specimens can be achieved. Discrimination of cancer cells from noncancer cells is by AO green fluorescence and discrimination of lymphocytes from other cell types is by AO red fluorescence. Cancer cells are consistently enriched in the AO high green and red fluorescence region, although, for a given cell type, maximal enrichment is patient-dependent. Finally, cancer cell enrichment and lymphocyte exclusion can be done simultaneously. Cells from sputum were initially fixed, stained with AO, sorted on a dual parameter flow sorter, and classified into six groups corresponding to two ranges of green and three ranges of red fluorescence intensities. Cells of each region were stained by the method of Papanicolaou and differential counts were performed to determine the relative frequencies (i.e., purities) of leukocytes, macrophages, squamous cells, and cancer cells, in sorted and unsorted (i.e., control) samples. The average purity of leukocytes (81%), macrophages (6%), squamous cells (11%), and cancer cells (2%) varied markedly from sample to sample. However, the largest enrichment values (i.e., ratio of purity of a cell type in a sorted sample to its purity in the unsorted control sample) achieved for cancer cells consistently occurred for each patient sample in the region corresponding to high green and high red fluorescence intensities. Experimentally, a cancer cell average enrichment of sixteen-fold was obtained by this method. Additionally, fluorescence intensity ranges which increased the enrichment for macrophages by cell sorting typically excluded leukocytes and squamous cells, and vice versa. Finally, red fluorescence intensity was the primary discriminatory parameter for all cell types studied, although the additional use of green fluorescence intensity significantly increased cancer cell enrichment rates.(ABSTRACT TRUNCATED AT 400 WORDS)

Clinical application of flow cytometry: a review

A survey of the use of flow cytometry for clinical purposes is given. In the last decade the main clinical application of this technique has been measurements of cellular DNA content for estimation of cell cycle distribution and ploidy studies. A large body of data is now available on the presence of aneuploidy in different malignant diseases. By measurements with high resolution, the demonstration of abnormal cellular DNA content in several types of tumors can be of definite diagnostic value when combined with conventional diagnostic procedures. The prognostic significance of different types of DNA aberrations is so far not established. Attempts to monitor cancer treatment by studying altered cell cycle distribution have not been successful, although some applications are of potential value. The main reasons for this are the complexity of tumor tissue as well as difficulties with interpretation of altered cell cycle distribution caused by drug combinations. For further progress in this field more emphasis on other cell constituents than DNA measured by flow cytometry is desirable, either as single or as multiparameter measurements.