Patterns of tumor colony development over time in soft‐agar culture

Abstract

Human tumors were cultured by the two-layer soft-agar technique and the time course of tumor colony development was evaluated during periods of up to 6 weeks in culture. All colony counting was performed with an automated tumor colony counter (Omnicon; Bausch and Lomb, Inc, Rochester, NY, USA). This instrument provided colony counts per culture plate in six size categories from greater than 60 microns diameter colonies to greater than 149 microns diameter colonies. Six to 24 culture plates were used for each "growth curve", generally 24. Control (non-drug-treated) cultures were obtained from 117 tumors, of which 25 also provided enough cells to allow evaluation of the time course of colony development after exposure to cytostatic agents. The development of colonies in non-drug-treated plates usually demonstrated a lag phase, a logarithmic growth phase to maximum colony development and a subsequent deterioration of colonies. In spite of clumps seeded into the agar, real colony growth could be recognized by frequent colony counting of culture dishes, although the temporal patterns of growth were sometimes different if pure single-cell suspensions were compared with suspensions containing clumps from the same tumor. Drug pre-incubation caused changes in the temporal pattern of colony growth as well as in the total number of colonies. Some cultures showed drug sensitivity when evaluated at certain time points while evaluation at later time points showed only borderline drug effect or none at all. The potential utility of tumor colony growth curves in the clinical applications of tumor colony cultures is discussed.

A High-Throughput Soft Agar Assay for Identification of Anticancer Compound

“…Using traditional soft agar methods to manually count colonies would be difficult and cumbersome for an HTS assay. Several different endpoints have been employed to quantitate colony formation, including manual counting of colonies in 6-or 24-well plates, 1,16,17 and in a limited scale by 3-H thymidine incorporation and high-content analysis. 18,19 Many of these assay methods require 3 to 4 weeks of growth before the colonies can be enumerated, and the counting of each well is labor intensive.…”

Cytopress: Automated slide preparation of cytologic material from suspension

“…To improve this visual and qualitative evaluation, new techniques for cell interpretation are being developed. Our laboratory is involved in this research, developing, among others, specific immunohistochemical stains to detect the tissue origin of tumor cells (18)(19)(20)(21), to detect quantitative morphologic and cytochemical changes using image analysis derived techniques (6,30,31), and to assess the malignant behavior of tumor cells in an in vitro model system (5,8,9,27). These new techniques require the preparation of reproducible, well-standardized specimens with homogeneously dispersed, nonoverlapping, single cells or cell groups.…”

Time course of ovarian tumour growth in soft agar culture

“…Assessment of growth, based on single day colony counts, ignores the fact that colony development of different tumours under different conditions may follow different patterns of temporal growth (Kirkels et al, 1983 Culture method All material was cultured in a double layer soft agar culture system as described in detail by Hamburger & Salmon (1980 Hamburger & Salmon (1980), except that conditioned medium and mercaptoethanol were not used.…”