Effect of glutamine deprivation and glutamate or ammonium chloride addition on growth rate, metabolism and differentiation of human colon cancer cell-line HT29

Abstract

1. 1. Effect of glutamine deprivation (GLN- medium) and of its replacement by 4mM ammonium chloride (GLN-/NH 4+ medium) or by 4mM glutamate (GLN-/Gt+ medium) was studied on growth rate, morphology and metabolism of HT29 human colon cancer cells. 2. 2. Growth rates were modified as follows: at the first passage, growth of GLN- cells was strongly decreased (doubling time: 192 hr vs 32 hr in control cells grown in GLN + medium); GLN-/NH4+ cells and GLN — /Gt + cells were found to have doubling times of 72 and 70 hr, respectively. At the 8th passage. doubling times were decreased in all cases, being: 144 hr for GLN- cells, 60 hr for GLN-/NH4+ cells and 24 hr for GLN-/Gt+ cells, which indicates a capacity of adaptation of the cell-line to new culture conditions. 3. 3. GLN- cells and GLN-/NH4+ cells were found to exhibit an enterocytic type of differentiation (polarization of the cell layer with apical and cystic brush border and tight junctions): GLN - /Gt + cells remained undifferentiated and comparable to control GLN+ cells. 4. 4. Glycogen level varied according to the phases of the culture, with a trend to lower level in glutamine deprived cells; glucose uptake and lactate production varied as a function of the medium composition and of the phases of the culture. At the 8th passage, all the glutamine deprived cells produced less lactate than control: GLN-/Gt + cells were found to utilize less glucose than others.