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The development of an anchorage-independence assay using human lung tumor cells to screen potential chemopreventive
E A Korytynski1, G J Kelloff, W A Suk
1ManTech Environmental Technology, Inc., Research Triangle Park, N.C. 27709, USA.
Abstract:
Advances in tumor biology research have led to the possibility of early detection of cancers and rational intervention of cancer development using chemopreventive agents. A significant number of potential chemopreventive agents have been identified from epidemiological surveys, independent research efforts, clinical data or based on structural homology with known chemopreventive agents. We have developed a fast, reliable in vitro model for screening potential chemopreventive agents using inhibition of anchorage-independent growth of a human lung tumor cell line, A427.A427 cells were plated in soft agarose containing a known chemopreventive agent, 13-cis-retinoic acid as the test agent and allowed to develop colonies for 28 days. A cytotoxicity test was used concurrently with anchorage independent assay for measuring the relative survival of cells to ensure that any observed inhibition of anchorage independent growth is due to the biological activity of the chemopreventive agent and not due to cellular toxicity. At the end of 28 days of growth, the stained colonies were enumerated, and the inhibition of spontaneous colony formation was measured. 13-cis-Retinoic acid inhibited the growth of A427 colonies in a concentration dependent manner. Data from 25 successive experiments indicate that a concentration of 33 microM consistently inhibited colony formation by 66.2 +/- 16.5 percent, ranging from 27 to 96.1% inhibition. This assay is a useful tool for screening potential chemopreventive agents, as it uses human cells as substrates rendering the efficacy data feasible for direct extrapolation to humans.
Insights
A new in vitro model effectively screens chemopreventive agents by measuring their ability to inhibit human lung tumor cell growth. This reliable method aids in identifying potential cancer interventions.
Area of Science:
- Oncology
- Cancer Biology
- Drug Discovery
Background:
- Tumor biology research enables early cancer detection and intervention with chemopreventive agents.
- Potential chemopreventive agents are identified through various methods including epidemiological surveys and clinical data.
- Developing efficient screening models is crucial for identifying novel cancer chemopreventive agents.
Purpose of the Study:
- To establish a fast and reliable in vitro model for screening potential chemopreventive agents.
- To evaluate the efficacy of 13-cis-retinoic acid as a chemopreventive agent using the developed model.
- To ensure observed inhibition is due to biological activity, not cellular toxicity.
Main Methods:
- Utilized a human lung tumor cell line (A427) in an in vitro soft agarose assay.
- Assessed inhibition of anchorage-independent growth of A427 cells over 28 days.
- Conducted concurrent cytotoxicity tests to validate chemopreventive effects.
Main Results:
- 13-cis-retinoic acid demonstrated concentration-dependent inhibition of A427 colony formation.
- A consistent inhibition of 66.2% (±16.5%) was observed at 33 microM concentration.
- The assay showed a wide range of inhibition from 27% to 96.1% across experiments.
Conclusions:
- The developed in vitro assay is a valuable tool for screening chemopreventive agents.
- The model's use of human cells allows for feasible extrapolation of efficacy data to humans.
- This method supports the rational intervention of cancer development through effective chemoprevention.