Short-term cryopreservation of human breast carcinoma cells for flow cytometry

Breast Organotypic Cancer Models

Breast cancer is the most common cancer type diagnosed in women, it represents a critical public health problem worldwide, with 1,671,149 estimated new cases and nearly 571,000 related deaths. Research on breast cancer has mainly been conducted using two-dimensional (2D) cell cultures and animal models. The usefulness of these models is reflected in the vast knowledge accumulated over the past decades. However, considering that animal models are three-dimensional (3D) in nature, the validity of the studies using 2D cell cultures has recently been questioned. Although animal models are important in cancer research, ethical questions arise about their use and usefulness as there is no clear predictivity of human disease outcome and they are very expensive and take too much time to obtain results. The poor performance or failure of most cancer drugs suggests that preclinical research on cancer has been based on an over-dependence on inadequate animal models. For these reasons, in the last few years development of alternative models has been prioritized to study human breast cancer behavior, while maintaining a 3D microenvironment, and to reduce the number of experiments conducted in animals. One way to achieve this is using organotypic cultures, which are being more frequently explored in cancer research because they mimic tissue architecture in vivo. These characteristics make organotypic cultures a valuable tool in cancer research as an alternative to replace animal models and for predicting risk assessment in humans. This chapter describes the cultures of multicellular spheroids, organoids, 3D bioreactors, and tumor slices, which are the most widely used organotypic models in breast cancer research.

Action of tolytoxin on cell morphology, cytoskeletal organization, and actin polymerization

Tolytoxin, a cytostatic, antifungal macrolide produced by blue-green algae of the genus Scytonema, is a potent, reversible inhibitor of cytokinesis in cultured mammalian cells. Treatment of KB cells with 2-16 nM tolytoxin results in profound morphological changes, beginning with the formation of zeiotic processes and culminating in nuclear protrusion. In L1210 cells, cytokinesis is inhibited by as little as 2 nM tolytoxin, while karyokinesis proceeds normally, resulting in polynucleation. Tolytoxin specifically disrupts microfilament organization in A10 cells, while having no apparent effect on microtubules or intermediate filaments. Tolytoxin inhibited actin polymerization in vitro and also caused the depolymerization or fragmentation of F-actin in vitro. Tolytoxin exhibits effects that closely resemble those of cytochalasin B but is effective at concentrations 1/50-1/1,000 that of cytochalasin B.

Expression of MDR1 and GST-pi in human soft tissue sarcomas: relation to drug resistance and biological aggressiveness

Human soft tissue sarcomas (HSTS) in adults are a family of mesenchymal tumors characterized by high biological aggressiveness and general refractoriness to chemotherapy. A series of 36 HSTS, 24 untreated and 12 homogeneously treated with a presurgical chemotherapeutic regimen consisting of doxorubicin (intra-arterial) and iphosphamide (intra-vein), was analyzed for expression of MDR1 and the glutathione-S-transferase-pi (GST-pi) gene in order to identify molecular phenomena which may be implicated in the chemoresistance displayed by these tumors. The MDR1 gene was expressed in a greater percentage of drug-treated tumors and at higher levels than in untreated ones. By contrast, chemotherapeutic treatment has no effect on GST-pi mRNA expression. The GST-pi expression level (EL) was much higher in the HSTS with biologically aggressive features. In fact, significant correlations were observed between GST-pi and histologic grade (p = 0.01); aneuploidy (p less than 0.01); and histone H3 EL (p = 0.01), suggesting a possible causal relationship between GST-pi activity and biological aggressiveness in HSTS.

Comparative evaluation of fresh, fixed, and cryopreserved solid tumor cells for reliable flow cytometry of DNA and tumor associated antigen

Five different protocols for the short-term preservation of cells used for multiparameter flow cytometric assay of tumour associated antigens (TAA) and DNA were assessed in cell suspensions prepared by mechanical disaggregation of 15 gynecological tumors. The protocols at 4 degrees C were 1) storage in buffer, 2) storage in 50% methanol, and 3) storage in buffer after formalin fixation. Tissues were also cryopreserved as cell suspensions and tissue blocks. When the TAA expression and DNA histograms of the preserved cells were compared with those in fresh cell suspensions, cryopreservation was found to be the best method: TAA expression was well preserved and there was a good correlation between TAA expression and the quality of the DNA histograms, respectively, in fresh and cryopreserved cells (RS: 0.82-0.91, P less than 0.001 for all TAAs). The cell suspensions preserved at 4 degrees C all showed a significant increase in background fluorescence (P less than 0.05) and a reduction in the TAA specific fluorescence (P less than 0.011). Methanol fixation was better than buffered formalin for the proteins studied, though both gave significantly worse results than cryopreservation. The quality of these cell suspensions and the correlation with TAA measurements in fresh cell suspensions deteriorated progressively with time, particularly if they were stored more than a week.

Regional heterogeneity in breast carcinoma: thymidine labelling index, steroid hormone receptors, DNA ploidy

We examined multiple samples of 65 primary breast carcinomas larger than 1 cm in diameter for thymidine labelling index (TLI), DNA index (DNAI, a measure of cellular DNA content by flow cytometry), and estrogen (ER) and progesterone (PgR) receptors by radioligand-binding. One or more axillary metastases were also assayed in 11 patients. Two to 15 samples were successfully assayed for TLI from 59 tumors, 2-31 samples for DNAI from 61 tumors, and 2-15 samples from 55 tumors for ER and PgR. Criteria for heterogeneity were excess inter-sample variance in comparison with intrasample variance at the p less than 0.05 level for TLI and DNAI, and variation of clinically significant magnitude in assay results for ER and PgR. Sixty-one percent of tumors were heterogeneous for TLI, 26% for DNAI, 24% for ER and 40% for PgR. High TLI disposed toward heterogeneity for TLI itself (p = 0.06), for ER (p = 0.04), and for PgR (p = 0.007). Young age favored heterogeneity for TLI (p = 0.12), ER (p = 0.002), and PgR (p = 0.04). Heterogeneity for DNAI was not related to age and TLI status but was more common in larger tumors (p = 0.08). After consideration of relationships between TLI, age, size, ER and PgR, TLI rather than age appears to be the more important determinant of heterogeneity for receptors. High TLI could lead to heterogeneity through increased numbers of cell divisions that favor emergence of variant stemlines, or by causing local vascular and humoral disparities through rapid growth. Regional heterogeneity can explain erroneous prognostic predictions in approximately 10% to 20% of breast carcinoma patients. We recommend multiple sampling of large breast carcinomas and analysis of axillary metastases for study of tumor markers.

Micromolar aluminum levels reduce 3H-thymidine incorporation by cell line UMR 106-01

Aluminum-induced osteomalacia is a frequent complication observed in patients on maintenance hemodialysis. However, it is not known whether there are direct effects of aluminum on osteoblasts, or alternatively, whether the observed changes are due to changes in PTH or other factors. We sought to determine the effect of micromolar levels of aluminum on osteoblasts using a well-defined cell line derived from a 32P induced osteosarcoma of rat, UMR 106-01, which is alkaline-phosphatase positive, responds to PTH, and synthesizes type I collagen. Aluminum exposure was controlled using tissue culture media with [Al ] less than 1 microgram/liter (40 nM), produced by precipitation of aluminum salts at pH 8.5. The effect of defined [Al ], from 20 to 800 micrograms/liter (0.7 to 30 microM), was then determined by adding back aluminum while measuring DNA and protein synthesis. We found that aluminum depressed DNA synthesis, as determined by 3H-thymidine incorporation, by 60%, with half maximal effect at 20 micrograms/liter (740 nM) in cells at a density of 20,000/cm2. Alternatively, protein synthesis, as determined by 3H-leucine incorporation, did not decline, and in some cases increased. However, qualitative analysis of matrix proteins produced with and without 800 micrograms/liter (30 mM) [Al ] showed no differences. Direct measurements of cell number and protein synthesis confirmed these findings. Al does not alter the PTH-induced cAMP response of these cells. Thus, aluminum has a direct effect on cell division, and probably on protein synthesis, in this osteoblast-like cell line. These effects occur at levels of aluminum below those commonly contaminating tissue culture media, and thus are seen reproducibly only in media of defined [Al ].(ABSTRACT TRUNCATED AT 250 WORDS)

Flow cytometric analysis of breast needle aspirates

This study investigated two hypotheses: (1) sufficient cells may be obtained by needle aspiration of breast nodules to produce good flow cytometric DNA profiles; and (2) benign breast lesions do not produce aneuploid G0G1 peaks, and therefore a distinct aneuploid peak is sufficient for a diagnosis of malignancy. Breast specimens received in Surgical Pathology between December 1985 and February 1987 were aspirated, and the cells stained with propidium iodide for flow cytometric DNA analysis. A total of 344 specimens were aspirated, of which 204 (59%) were malignant and 140 (41%) benign. One hundred fifty-three malignant and 111 benign specimens contained sufficient cells for analysis. Cytologic smears were available for 177 malignant and 123 benign specimens. DNA histograms were considered diagnostic of malignancy if an aneuploid peak was present which contained at least 20% of the cells in the distribution, and had a DNA index greater than or equal to 1.2. Using these criteria, 73 of 153 (48%) carcinomas could be identified. None of the benign lesions satisfied these criteria. One fibroadenoma with atypical hyperplasia produced a distinct peak which contained less than 5% of the cells in the histogram, and had a DNA index of 1.25. Flow cytometric analysis provides objective data that complement the subjective cytologic interpretation of fine needle aspirates.

Flow cytometry: methodology and applications in pathology

Flow cytometry offers pathologists a powerful new method which can be applied especially for diagnosis, prediction of prognosis and measurement of response to therapy of tumours. It also has a wide variety of other applications in research and its use for investigation of non-neoplastic disease has only just begun. The object of this brief review is to stimulate interest in this technique and to outline some of the most interesting applications that may be of use to pathologists in the near future.

A proposed classification of breast cancer based on kinetic information: derived from a comparison of risk factors in 168 primary operable breast cancers

Flow cytometric DNA analysis was performed on 168 consecutive primary operable breast cancers and the results correlated with thymidine labeling, estrogen receptor (ER) and progesterone receptor values, and various histologic parameters. Seventy-five cancers (45.0%) were diploid and 93 (55.0%) aneuploid. In 83.9% of aneuploid cancers, the DNA index fell between 1.1 and 2.0. Thirteen cancers were hypertetraploid and three hypodiploid. The percent of S-phase cancers (SpF) varied from 1.1% to 24.4%, with a mean of 8.0% and a median of 7.1%. The mean SpF of diploid cancers was 5.2%; of aneuploid cancers, 10.3%. There was no significant correlation between SpF or ploidy and tumor size or axillary lymph node status. The thymidine labeling index (TLI) varied from 0.2 to 23.1, with a mean of 7.5 and a median of 6.1. There was good correlation between TLI and SpF (r = 0.892, P = 0.0001). ER-negative tumors had a significantly higher mean SpF (10.3%) than did ER-positive tumors (6.7%), but there was no significant correlation between ploidy and receptor positivity or negativity. There was a good correlation between invasive tumor necrosis, poor cytologic differentiation, aneuploidy, and above-median SpF. Only a fair correlation was observed between mitotic rate and SpF. A classification of invasive breast cancers based on ploidy and SpF is proposed.