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Monensin and tunicamycin-induced inhibition of HT29 cell spreading and growth
Abstract:
HT29 cells originating from a human colon adenocarcinoma, spread very rapidly after seeding on their own extracellular matrix (ECM). Preincubation of cells with the inhibitor of protein glycosylation tunicamycin (TM) or with the ionophore monensin substantially suppressed cell spreading in serum-free medium without affecting cell adhesion to ECM. Addition of the drugs after cell attachment and spreading inhibited cell growth. TM-treated cells remained viable after 6 days of exposure to 2 micrograms ml-1 of TM and resumed their normal growth rate and shape after removing the drug from the medium. On the contrary, monensin inhibition of cell growth was not reversible: after 3 days, cells detached from the ECM and were unable to exclude Trypan Blue. At the ultrastructural level, a swollen Golgi apparatus with numerous vacuoles was observed after treatment for 2 h in either TM or monensin-preincubated cells. These results suggest that TM and monensin interfere with the insertion and, or, function of one or more cell surface glycoproteins, possibly interacting with cytoskeleton and involved in cell spreading and growth.
Insights
Tunicamycin (TM) and monensin inhibit colon cancer cell spreading and growth by interfering with cell surface glycoproteins. TM
Area of Science:
- Cell Biology
- Biochemistry
- Cancer Research
Background:
- HT29 colon adenocarcinoma cells exhibit rapid spreading on extracellular matrix (ECM).
- Understanding factors influencing cancer cell adhesion and growth is crucial for therapeutic development.
Purpose of the Study:
- To investigate the effects of tunicamycin (TM) and monensin on HT29 cell spreading, adhesion, and growth.
- To elucidate the molecular mechanisms underlying TM and monensin's impact on cell surface glycoproteins and cytoskeleton interactions.
Main Methods:
- Utilized HT29 cells cultured on their ECM in serum-free medium.
- Administered TM and monensin to assess effects on cell spreading, adhesion, and growth.
- Performed ultrastructural analysis of Golgi apparatus morphology.
- Evaluated cell viability and reversibility of drug effects using Trypan Blue exclusion.
Main Results:
- TM and monensin significantly suppressed HT29 cell spreading without affecting adhesion to ECM.
- Both drugs inhibited cell growth when added post-attachment.
- TM treatment allowed for reversible inhibition of growth and restoration of normal cell morphology.
- Monensin induced irreversible growth inhibition, leading to cell detachment and death.
- Ultrastructural analysis revealed Golgi apparatus swelling in response to both TM and monensin.
Conclusions:
- TM and monensin interfere with cell surface glycoprotein insertion and/or function, impacting cell spreading and growth.
- These glycoproteins likely interact with the cytoskeleton, playing a role in cell morphology and proliferation.
- Monensin's effects are irreversible, suggesting a more profound disruption of cellular processes compared to TM.