Differentiation capacity of human non‐small‐cell lung cancer cell lines after exposure to phorbol ester

Abstract

Three cell lines of squamous-cell carcinoma and 3 of large-cell carcinoma origin were investigated for the expression of differentiation markers and functional parameters (proliferation, morphology, cornified envelope formation, involucrin staining, transglutaminase activity, adhesiveness and migration) under normal cell culture conditions and after treatment with the tumor promoter phorbol-12-myristate-13-acetate (PMA). Although all original tumors had been described as poorly differentiated by histological grading, we found significant heterogeneity in the expression of differentiation markers in cell culture. A systematic grading of the cell lines became possible only after PMA stimulation. PMA generally increased expression of differentiation markers in cell lines of comparably low grades of differentiation, as indicated by dose-dependent inhibition of proliferation and cloning efficiency, induction of squamous markers, and decreased adhesiveness and cell motility. In contrast, cell lines of apparently higher differentiation by these criteria showed little response to PMA. The results presented show that the assessment of differentiation capacity by comparison of differentiation markers under normal cell culture and PMA-stimulated conditions in established NSCLC cell lines allows for a refined cell culture grading, which might advance the classification and characterization of such cell lines which, otherwise, appear to be very heterogeneous. It may also help to correlate cellular functions with various states of differentiation in vitro.

Effect of intravenous infusions of 12-O-tetradecanoylphorbol-13-acetate (TPA) in patients with myelocytic leukemia: Preliminary studies on therapeutic efficacy and toxicity

“…The results of our studies indicating that TPA can be administered to patients without overt serious toxicity suggests the possible use of TPA for the treatment of solid tumors. TPA (1-15 nM) has been shown to enhance differentiation, increase apoptosis, and͞or to inhibit DNA synthesis and cell proliferation in studies with cultured human breast cancer MCF-7 cells (21), human colon cancer VACO 10MS cells (22), a human non-small-cell lung cancer cell line (23,24), the human LNCaP prostate cancer cell line (25)(26)(27)(28), and some human melanoma cell lines (29) in vitro. The possibility of effective treatment of patients with these solid tumors by the use of TPA alone or in combination with other chemotherapeutic drugs should be considered.…”

Inhibitory Effects of 12-O-Tetradecanoylphorbol-13-acetate Alone or in Combination with All-trans Retinoic Acid on the Growth of Cultured Human Pancreas Cancer Cells and Pancreas Tumor Xenografts in Immunodeficient Mice

“…In studies with cultured cells from solid tumors, TPA was shown to inhibit the growth, stimulate apoptosis, or enhance differentiation in human tumor cell lines derived from patients with melanoma, prostate, breast, colon, or lung cancer (Guilbaud et al, 1990;Salge et al, 1990;Arita et al, 1994;Garzotto et al, 1998;Rickard et al, 1999). Treatment of prostate cancer LNCaP cells with clinically achievable concentrations of TPA (1-1.6 nM) resulted in growth inhibition (Konno et al, 1996;Powell et al, 1996;Garzotto et al, 1998;Fujii et al, 2000), and treatment of these cells with a severalfold higher concentration of TPA caused apoptosis (Konno et al, 1996;Powell et al, 1996;Garzotto et al, 1998;Fujii et al, 2000).…”

12-O-tetradecanoylphorbol 13-acetate induced differentiation in human lung squamous carcinoma cells

“…Other cell lines derived from poorly differentiated squamous carcinomas are reported to have levels between 0 and 60% (Banks-Schlegel et al, 1985;Levitt et al, 1990;Salge et al, 1990). The percentage of cells positive for involucrin was similar as was the proportion of cells positive for cytokeratin 13 and it is very possible that all three markers are associated with the same cell subpopulation.…”

“…The factors that control proliferation and differentiation in this disease are poorly understood and an improved knowledge of these might aid the development of therapeutic strategies such as the use of differentiation induction in this tumour type (Bloch, 1984;Sartorelli, 1985). Lung squamous carcinoma cells undergoing terminal differentiation demonstrate a number of features including expression of involucrin (a protein precursor found beneath the plasma membrane prior to terminal differentiation) and the ability to form cornified envelopes (Miyazaki et al, 1982;Banks-Schlegel et al, 1985;Levitt et al, 1990;Said et al, 1983;Salge et al, 1990 (Broers et al, 1988).In the present study, we describe differentiation features within three new cell lines and show how they relate to the xenografts from which they were derived. The effect of the differentiation inducer 12-O-tetradecanoylphorbol 13-acetate (TPA) on the growth and differentiation of these cell lines was then investigated.…”