A predictive assay for human tumor cellular response to hyperthermia using dansyl lysine staining and flow cytometry

Our plain-English summary of A predictive assay for human tumor cellular response to hyperthermia using dansyl lysine staining and flow cytometry, by S.Y. Woo, G.C. Rice, D.S. Kapp, et al (International Journal of Radiation Oncology, Biology, Physics, 1988).

The study

• Authors: S.Y. Woo, G.C. Rice, D.S. Kapp, G.M. Hahn
• Journal: International Journal of Radiation Oncology, Biology, Physics
• Published: 1988;14(2):361-5
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The heat response of five human tumor biopsies has been examined using the fluorescent probe dansyl lysine and multiparameter flow cytometry. Dansyl lysine has previously been shown to possess specificity for heat killed mammalian cells. The human tumors tested included a cervical squamous cell carcinoma, malignant melanoma, colon adenocarcinoma, ovarian carcinoma, and a mesothelioma. The samples were excised, mechanically disrupted into single cell suspensions and heated in vitro for various lengths of time at 45 degrees C. The cells were returned to 37 degrees C incubation for 12 to 15 hours prior to staining with dansyl lysine. The fraction of cells staining dansyl lysine was quantitated by flow cytometry after gating on high forward angle light scatter and 90 degrees C light scatter. This gate excluded much of the normal cell contamination within the tumor sample. The data show that the heat response of human tumor biopsies varied significantly, with cervical carcinoma and malignant melanoma being the most resistant and the mesothelioma and ovarian carcinoma the most heat sensitive. Finally, evidence is presented for the expression of thermotolerance in ovarian carcinoma and mesothelioma biopsies pre-heated in vitro. Dansyl lysine appears to be useful in measuring the intrinsic cellular heat sensitivity of human tumors and in determining the kinetics of decay of thermotolerance following an initial heat exposure.

In plain English

This brief laboratory report tested whether a fluorescent dye, dansyl lysine, which stains heat-killed cells, could be combined with flow cytometry to measure how cells from human tumors respond to heat. The authors used single samples of five tumors removed at surgery: a colon adenocarcinoma, a malignant melanoma, a cervical squamous cell carcinoma, an ovarian carcinoma and a malignant mesothelioma. The article does not say where in the body the mesothelioma arose and does not mention asbestos. Cells were separated, heated in the laboratory at 45°C for various times (the melanoma at 44°C), and the fraction of cells that did not take up the dye was counted. Responses varied widely. At 60 minutes, the melanoma and cervical carcinoma were about 4 to 5 times more heat resistant than the colon adenocarcinoma, the mesothelioma and the ovarian carcinoma. When the mesothelioma and ovarian samples were preheated, more cells excluded the dye after a later 60-minute heating. The authors interpreted this as likely thermotolerance (acquired heat resistance). The authors concluded the method was feasible. They noted heavy contamination by normal cells and other limitations.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: laboratory (in vitro) feasibility study of human tumor biopsy cells; brief communication
• Who was studied: Samples from five human tumors obtained at surgical excision: colon adenocarcinoma, malignant melanoma, cervical squamous cell carcinoma, ovarian carcinoma and a malignant mesothelioma (Department of Therapeutic Radiology, Stanford University; dates not given)
• Exposure: Heat (hyperthermia) applied in vitro at 45°C for various lengths of time (melanoma at 44°C), followed by 12 to 15 hours at 37°C and dansyl lysine staining; no asbestos exposure is studied
• Main results:
  • Before heating, the fraction of cells excluding the dye after dispersal was lowest for the malignant mesothelioma, at 36% (Table 1: ovarian carcinoma 78%, malignant melanoma 95%, colon adenocarcinoma 87%, cervical squamous cell carcinoma 44%)
  • At 60 minutes of heating, the melanoma and cervical carcinoma were approximately 4 to 5 times more heat resistant, as measured by dye exclusion, than the colon adenocarcinoma, mesothelioma and ovarian carcinoma
  • Preheating at 45°C for 10 minutes (mesothelioma) or 20 minutes (ovarian carcinoma) gave higher dye exclusion after a later 60-minute heating than in unpreheated cells of the same tumors, which the authors took as likely thermotolerance
• The authors' conclusion: The authors concluded that the studies demonstrated the feasibility of measuring human tumor heat response with dansyl lysine and flow cytometry, and that the assay may be useful for data on the intrinsic heat sensitivity of tumors
• Limitations the authors state:
  • Contamination by non-malignant cells was a serious problem in nearly all samples, and the gating used probably selects only a subset of the tumor cells
  • Cells must be disaggregated into a single-cell suspension, and specific subpopulations may be differentially sensitive to the disruption methods
  • Additional data are needed on cell differences within a tumor, local environmental factors, and uneven heating throughout the tumor
  • Tumor response to heat may depend on effects on blood vessels rather than on tumor cell survival, so cellular assays may not predict tumor response

Topics

Medical terms in this study, explained in our Lexicon: Squamous Cell Carcinoma, Adenocarcinoma, Carcinoma, Mesothelioma.

Related studies

• Flow cytometry in the exploration of the physiopathology of occupational lung disease — A.D. Curran (1999)
• Hyperthermia and mafosfamide in a human-derived malignant pleural mesothelioma cell line — E.M. Ehlers, W. Kühnel, et al. (2002)
• Flow cytometric measurement of cellular FLICE-inhibitory protein (c-FLIP) in ovarian carcinoma effusions — H.P. Dong, A.K. Ree Rosnes, et al. (2011)
• Complete pathological response to neoadjuvant pemetrexed/cisplatin in combination with regional hyperthermia in a patient with sarcomatoid peritoneal mesothelioma — S. Kruger, M.K. Angele, et al. (2014)
• Radio frequency hyperthermia of advanced human sarcomas — F.K. Storm, R.S. Elliott, et al. (1981)
• DNA analysis by flow cytometry in malignant pleural mesothelioma: relationship to histology and survival — H. Dazzi, N. Thatcher, et al. (1990)

Browse return to medical research.