Modulation of growth, differentiation and glycoprotein synthesis by β‐ALL‐trans retinoic acid in a multicellular tumor spheroid model for squamous carcinoma of the head and neck

Abstract

Cell line MDA 886Ln was established from a laryngeal lymph node metastasis. When grown as a multicellular tumor spheroid (MTS), it exhibits squamous differentiation. We studied the effects of beta-all-trans retinoic acid (RA) on the growth, differentiation and glycoprotein content of this MTS model for squamous carcinomas of the head and neck. The growth of MTSs was inhibited in a dose-dependent manner by 10(-6) to 10(-10) M RA. Growth inhibition occurred between 3 and 5 days of RA treatment (10(-6)M). Immunohistochemical and electrophoretic analyses revealed that RA suppressed the morphological markers of squamous differentiation (squames), involucrin expression, and keratin expression. Gly-coprotein expression was examined by metabolic labelling using 3H-glucosamine, in situ labelling of polyacrylamide gels with 125I-labelled wheat-germ agglutinin (WGA), localization of fluorescein isothionate-WGA in frozen sections, and determination of sialyltransferase activity. Treatment using 10(-6) M RA altered glycoprotein expression both biochemically and morphologically, and WGA was shown to bind preferentially to sialic acid residues. The sensitivity of this MTS model to RA treatment and its ability to be analyzed through morphological, immunohistochemical and biochemical techniques suggest that it will prove useful in studying the relationships between growth, differentiation and RA-induced alterations in squamous carcinomas.

Keratin expression and its significance in five cultured melanoma cell lines derived from primary, recurrent and metastasized melanomas

“…Although highly concentrated salt and detergent (KC1, NaCl and Triton X-100) have been employed by many researchers to prepare keratin subunits from malignant neoplasms [23,24], cultured SCC [25,26] and melanoma cell lines [10,11], these reagents were originally used on native tissues or tumors to remove large amounts of subcutaneous fat tissues [27,28]. In fact, we demonstrated previously that this aqueous solution was more efficient than the high salt solution (1.5 M KCl/1% Triton X-100/150 mM NaCl/10 mM Tris-HCl (pH 7.4)/5 mM EDTA/PMSF (10 ug/ml)) [27] for detection of keratin subunits in cultured SCC [13][14][15] and melanoma cell lines [12].…”

Innate cellular fluorescence reflects alterations in cellular proliferation

“…In a multicellular tumor spheroid model, trans-retinoic acid (RA) altered autofluorescence profiles as assessed with multiple wavelengths including the excitation scans (ex 220-360 nm, em 380 nm), (ex 260-430 nm, em 450 nm), and the emission scans (ex 300 nm, em 320-580 nm), (ex 340 nm, em 360-660 nm) [18]. Such RA-induced alterations corresponded to changes in the state of spheroid differentiation [19,20]. In vivo human studies are in progress which suggest that neoplastic tissues within the upper aerodigestive tract can be discriminated from normal mucosa by their autofluorescence profile.…”

A multicellular tumor spheroid model of cellular immunity against head and neck cancer

“…In studies aimed at understanding natural killer cell function for tumors of the upper aerodigestive system, we have used a series of SCC cell lines in addition to the standard K562 target, as results produced with such cells may be more clinically relevant [17,18]. An MTS model for squamous carcinoma of the head and neck has recently been established [11,14,15]. MTS have an organizational complexity intermediate between monolayer cultures and in vivo tumors.…”