Flow cytometry: Potential utility in monitoring drug effects in breast cancer

Abstract

Flow cytometric analysis of DNA ploidy and S-phase fraction are well recognized prognostic indicators in breast cancer. The present paper deals with the widening of the applications of flow cytometry to monitoring the effectiveness of antiestrogen therapy, detecting clonal selection and emergence of drug resistance, and monitoring chemosensitizing properties of drugs. Antiestrogen activity can be studied by DNA flow cytometry to address clinical research problems such as patient-specific pharmacokinetics, dosing compliance, and acquired antiestrogen resistance. Patient plasma specimens containing various concentrations of triphenylethylenes can be monitored for drug-induced effects using cell cycle measurements and correlated to in vivo drug levels. DNA flow cytometry has also been instrumental in the study of the effects of prolonged low-dose (0.5 microM for > 100 days) tamoxifen treatment on human estrogen receptor negative MDA-MB-231 cells, where it was shown that tamoxifen may significantly alter cell cycle kinetics and tumorigenicity of these cells, selecting a new, more aggressive, and rapidly growing clone. Lastly, it has been shown that the chemosensitizing properties of another triphenylethylene antiestrogen, toremifene, on estrogen receptor negative, multidrug resistant MDA-MB-231-A1 human breast cancer cells can be studied using flow cytometric analysis. Toremifene (and its metabolites N-desmethyltoremifene and toremifene IV) are able to "resensitize" MDA-MB-231-A1 cells to vinblastine and doxorubicin, as reflected in a marked shift of cells to G2/M phase of the cell cycle. Flow cytometry is a widely available technique that might be applied clinically to monitor, at the cellular level, drug effects on tumors, including the modulators of drug resistance.

Biophotonics for blood analysis

“…FCM may be incorporated in a wealth of different studies, notably: cell cycle analysis (Sitton and Srienc, 2008;Calvert et al, 2008); apoptosis 4 (Lecoeur, 2002;Yasuda et al, 2005;Yasuhara et al, 2003) and stem cell investigations (Nolan and Yang, 2007;Castagnola et al, 2011); and drug effect trials (Koester et al, 1994;Morgan et al, 1989). Furthermore, FCM has been used in conjunction with other complementary modalities such as: photothermal and PA applications for the study of blood and lymph flows (Zharov et al, 2005(Zharov et al, , 2006b(Zharov et al, , 2007; applications in tumour analysis and fluorescence-based (Yi et al, 2006).…”

‘Go with the flow ’: A review of methods and advancements in blood flow imaging

“…Flow cytometry may be incorporated in a wealth of different studies, notably: cell cycle analysis [383,384]; apoptosis 7 [385][386][387] and stem cell investigations [388,389]; and drug effect trials [390,391]. Furthermore, flow cytometry has been used in conjunction with other complementary modalities such as: photothermal and photoacoustic applications for the study of blood and lymph flows (see Figure 30) [382,392,393]; applications in tumour analysis and fluorescence based breast cancer imaging [394][395][396][397]; Figure 29 Illustration of flow cytometric cell sorting [376].…”

pS2 Protein, EGFR and Cathepsin D in Association with Established Prognostic Factors in Early Recurrence of Breast Cancer1

“…The C-erb-B2 gene, which is structurally related but different from the EGFR gene, is amplified and over expressed with an incidence of up to 32% in human primary breast tumors and has been correlated with poor overall survival and early relapse [6]. There are conflicting reports regarding the clinical significance of DNA flow cytometry measurements of ploidy status, while measurements of the S-phase fraction indicate an association with a high risk of tumor recurrence [1,7]. Quite a few potential prognostic para meters, including expression of estrogen-regulated proteins and proteases, amplification and/or overexpression of onco genes and growth factors and their receptors such as pS2, cathepsin D and EGFR, have so far been studied, but no con sensus exists regarding their interrelationships and prognostic value [8,9], Differences in assay methodology, in the various definitions used for positivity/negativity, in patients selection and use of systemic adjuvant treatment might have influenced the outcome of the mostly retrospective studies and could pro vide possible explanations for the discrepant results reported [10][11][12], The aim of the present prospective study was to inves tigate the relationship between some of these factors such as pS2 protein, cathepsin D and EGFR and established prog nostic factors and to evaluate their potential prognostic value in early recurrence of breast cancer.…”