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Effect of pH on proteinase secretion by transformed fibroblast populations
J Chaloupka1, H Kucerová, L Váchová
1Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague.
Abstract:
Effect of pH on secretion of proteolytic enzymes in cell cultures of three clonal lines of transformed fibroblasts (K2, T15 and K4) was studied by using 14C-labelled denatured proteins as substrate. One line of malignant macrophages derived from mouse reticulum cell sarcoma (J774.1) was used for comparison. The relative motility index of all cell lines was derived by computer analysis of quantitative estimations of cell dispersion in single-cell-derived colonies. Cultivation at pH 6.5 decreased the growth rate in most experiments as compared with that at pH 7.4, and stimulated cell motility to a different extent. The population of mouse malignant macrophages produced several-fold higher extracellular proteolytic activity than the fibroblast lines. Secretion of proteinases by the malignant macrophages was significantly stimulated by the lower pH. Enzyme secretion by two of the three fibroblast derivatives was also stimulated by acidic pH but to a lesser extent than the secretion of the malignant macrophages. The assessment of motility done by measurement of dispersion of cells in colony proved a positive correlation between motility and proteinase secretion in J774.1 cells and one transformed fibroblast clone (T15) but not in the two other clonal lines.
Insights
Acidic pH (6.5) reduced growth but increased cell motility and proteolytic enzyme secretion in transformed fibroblasts and malignant macrophages. Macrophages showed higher enzyme activity and greater pH-induced stimulation.
Area of Science:
- Cell Biology
- Biochemistry
- Oncology
Background:
- Cellular microenvironment pH is a critical factor influencing cell behavior.
- Investigating the impact of pH on enzyme secretion and motility is crucial for understanding cancer progression.
Purpose of the Study:
- To investigate the effect of pH on proteolytic enzyme secretion and cell motility in transformed fibroblasts and malignant macrophages.
- To compare the responses of different cell lines to acidic pH conditions.
Main Methods:
- Utilized 14C-labelled denatured proteins as a substrate to measure proteolytic enzyme secretion.
- Assessed cell motility using computer analysis of cell dispersion in single-cell-derived colonies.
- Cultured three clonal lines of transformed fibroblasts (K2, T15, K4) and one line of malignant macrophages (J774.1) at different pH levels (6.5 and 7.4).
Main Results:
- Cultivation at pH 6.5 decreased growth rate and stimulated cell motility in most cell lines compared to pH 7.4.
- Malignant macrophages exhibited significantly higher extracellular proteolytic activity and enzyme secretion, which was strongly stimulated by acidic pH.
- Two of three fibroblast lines also showed increased enzyme secretion at acidic pH, but to a lesser extent than macrophages.
- A positive correlation between motility and proteinase secretion was observed in J774.1 cells and the T15 fibroblast clone.
Conclusions:
- Acidic pH selectively modulates cell motility and proteolytic enzyme secretion in transformed cells.
- Malignant macrophages are more sensitive to acidic pH, showing enhanced enzyme secretion and motility.
- The findings suggest a link between motility and proteinase secretion, particularly in malignant cells, under acidic conditions.