Origin of intracellular lumina in HT 29 colonic adenocarcinoma cell line

A kinetic study of horseradish peroxidase transport was carried out on short-term cultured adult rat hepatocytes. After 4 hr of plating, cells were preincubated with monensin (1 microM) for 1 hr before their incubation with horseradish peroxidase for different times. Monensin treatment resulted in the dilatation of the Golgi apparatus and caused the appearance of numerous intracellular lumina lined with microvilli in associated as well as isolated hepatocytes but did not modify newly formed bile canaliculi. The frequency of their appearance increased to 28% in cells pretreated with monensin compared to 2% in controls. Intracellular lumina membranes had the morphological features of apical membranes and were stained with horseradish peroxidase more frequently than those of newly formed bile canaliculi. This work therefore provides a model for studying bile secretion in cultured hepatocytes. Our results also suggest that the biliary transport of horseradish peroxidase does not involve the Golgi apparatus, since horseradish peroxidase was never observed in the Golgi stacks even after monensin treatment.

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“…Similar intracellular structures have been described previously in different cell types, particularly in malignant cell lines (12).…”

Section: Discussionsupporting

confidence: 85%

“…In many of these studies, ICL are present in the vicinity of Golgi stacks or when Golgi apparatus appears poorly developed, so that a Golgi origin of ICL has been suggested (12). This hypothesis is not completely supported by our data.…”

Section: Discussioncontrasting

confidence: 67%

The effects of monensin on the transport of horseradish peroxidase into intracellular lumina in cultured rat hepatocytes

et al. 1989

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“…when normal extracellular calcium levels are restored (Vega-Salas et al, 1987. In addition, intraepithelial lumens, formed between adjacent cells and bordered by tight junctions, have been described in developing intestinal epithelium (Remy, 1986) and in monolayers of HT-29 cells (Remy and Marvaldi, 1985). We observed VACs in approximately 20% of HT-29.74 cells following depolarization in low calcium medium (e.g., see Fig.…”

Section: High Cell Density Promotes Expression Of Scmentioning

confidence: 75%

Cell polarity regulates the release of secretory component, the epithelial receptor for polymeric immunoglobulins, from the surface of HT‐29 colon carcinoma cells

Chintalacharuvu

Piskurich

Lamm

et al. 1991

Journal Cellular Physiology

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The HT-29 human colon carcinoma cell line differentiates in glucose-free medium to an enterocytic phenotype. We previously isolated a series of HT-29 subclones selected for high levels of expression of secretory component (SC), the epithelial receptor for polymeric immunoglobulins. To develop a model system for studying effects of cell polarity on SC expression and release from the cell surface, the HT-29.74 subclone was induced to differentiate in glucose-free medium. Expression of SC was induced by glucose deprivation in both the parental HT-29 cell line and, to an even greater extent, in the HT-29.74 subclone. Prolonged glucose deprivation of HT-29.74 cells resulted in morphological changes consistent with enterocytic differentiation. Metabolic radiolabeling of SC in differentiated HT-29.74 cells indicated that proteolytic cleavage of membrane-bound to free SC occurred both on the cell surface and intracellularly, possibly in a vacuolar apical compartment or intrapeithelial lumen. To study effects of cell polarity on SC release, differentiated HT-29.74 cells were depolarized by culturing in low calcium medium. Within 2 hours after transfer of the cells into low calcium medium, a burst of SC release was observed concomitant with cell depolarization. Subsequently, release of SC declined significantly and remained low as long as cells were maintained in a depolarized state. The extent of cell depolarization could be controlled by varying the extracellular calcium concentration or by substituting the divalent cation Sr++, which partially prevents depolarization, for Ca++. In either case, the magnitude of the initial burst and subsequent decline in release of SC was proportional to the extent of cell depolarization. We conclude that cell polarity plays an important role in controlling the release of SC in intestinal epithelial cells, most likely by regulating the distribution of membrane-bound SC and SC protease, which are on the basolateral and apical cell surfaces, respectively, in differentiated cells.

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“…However, these observations were made from immortalized colonic epithelial cells, which may not precisely represent the inflammatory process in vivo. Certainly, HT‐29 cells are tumor cells derived from human colonic adenocarcinoma; as such, these cell lines have unique properties different from that of normal intestinal cells (eg, genetic makeup, metabolic profile, and other cellular physiological properties) 49 . The cell culture conditions in which these cells are maintained also do not typically represent the local environment in situ 50 .…”

Section: Discussionmentioning

confidence: 99%