Abstract

Both dibutyryl cyclic AMP and trypsinized concanavalin A have been shown to inhibit growth in certain cell lines but little testing of these substances has been done using human tumor cell lines. Further, there are at this time no published experimental attempts to correlate the effects on growth with a particular phase of the cell cycle in any cell line.

My experimental data show that the human tumor cell lines HeLa, HEp 2 and KB exhibit pronounced inhibition of growth when treated with trypsinized concanavalin A and reach a contact-inhibited state at a density far below that to which these cells normally grow. The inhibitory effect of trypsinized concanavalin A occurs by lengthening the Gl phase of the cell cycle in these cells.

Dibutyryl cyclic AMP also inhibits the growth of HeLa, HEp 2 and KB cell cultures. KB cells reach a contact-inhibited state at 8 x 104 cells/cm2 irrespective of the initial plating density. If dibutyryl is removed from KB cell cultures in the contact-inhibited state, growth resumes with DNA synthesis beginning in 6 to 8 hours. Experimental data suggest that the inhibitory effect of dibutyryl cyclic AMP occurs during Gl of the cell cycle.

In hamster cheek pouch tissue, dibutyryl cyclic AMP inhibits DNA synthesis. When an epithelial extract from cheek pouch tissue containing an epithelial chalone is combined with dibutyryl, the inhibitory effect on the DNA synthesis rate appears to be additive not synergistic.

LLU Discipline

Physiology

Department

Physiology

School

Graduate School

First Advisor

Raymond G. Hall, Jr.

Second Advisor

Kenneth A. Arendt

Third Advisor

Elwood S. McCluskey

Fourth Advisor

Yuk Lin Ho

Fifth Advisor

Ian M. Fraser

Degree Name

Doctor of Philosophy (PhD)

Degree Level

Ph.D.

Year Degree Awarded

1972

Date (Title Page)

6-1972

Language

English

Library of Congress/MESH Subject Headings

Neoplasms -- therapy; Dibutyryl Cyclic AMP; Concanavalin A

Type

Dissertation

Page Count

viii; 54

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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