Related Experiment Video
Updated: Oct 2, 2026
Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
Published on: January 7, 2013
Inhibitory effects of phytopolyphenols on TPA-induced transformation, PKC activation, and c-jun expression in mouse
1Institute of Biochemistry, College of Medicine, National Taiwan University, Taipei, Republic of China.
Abstract:
The effects of 12 phytopolyphenols, including 3 catechin derivatives, 8 flavanols, and curcumin, on 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced transformation in mouse fibroblast cells are described. The location of hydroxyl functional groups at 2', 3', or 4' site(s), especially at the 4' site, as in apigenin, fisetin, morin, myricetin, and quercetin, seems essential for anti-TPA-induced transformation, anti-protein kinase C (PKC) activation, and anti-TPA-induced c-jun expression activities. Among the catechin derivatives, those with a cis form structure and with an additional hydroxyl group at the R1 site and galloyl groups at the R2 site, such as epigallocatechin gallate, have stronger inhibitory effects on the above-mentioned biochemical activities. Considering their polarities and chemical structures, these compounds have different oxygen radical absorbance capacity in the in vitro assay. In addition, curcumin also has these inhibitory effects on the above-mentioned biochemical activities and antioxidant activities for peroxyl radical but not hydroxyl radical. In addition to PKC activation, active oxygen species production, and c-jun induction, our data suggest that TPA treatment induces cellular transformation by other unknown routes, because some tested compounds have an inhibitory effect on TPA-induced transformation but have no or a slight inhibitory effect on PKC activation, active oxygen species production, and c-jun induction.
Insights
Phytopolyphenols, including flavanols and curcumin, inhibit 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cell transformation. Hydroxyl group location and specific catechin structures are key for these anti-cancer effects.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- 12-O-tetradecanoylphorbol 13-acetate (TPA) is known to induce cellular transformation.
- Phytopolyphenols are plant-derived compounds with potential biological activities.
- Understanding the mechanisms of TPA-induced transformation is crucial for cancer research.
Purpose of the Study:
- To investigate the effects of 12 phytopolyphenols on TPA-induced transformation in mouse fibroblast cells.
- To identify structural features of phytopolyphenols responsible for anti-transformation activity.
- To explore the relationship between phytopolyphenol structure, protein kinase C (PKC) activation, and antioxidant properties.
Main Methods:
- Treatment of mouse fibroblast cells with TPA and various phytopolyphenols.
- Assays to measure TPA-induced transformation, PKC activation, and c-jun expression.
- In vitro antioxidant capacity assays (oxygen radical absorbance capacity).
Main Results:
- Specific hydroxyl group positions (e.g., 4' site) on flavanols were essential for inhibiting TPA-induced transformation, PKC activation, and c-jun expression.
- Epigallocatechin gallate demonstrated potent inhibitory effects due to its cis-form structure and specific hydroxyl and galloyl groups.
- Curcumin exhibited inhibitory effects on transformation and peroxyl radical scavenging but not hydroxyl radical scavenging.
- Some compounds inhibited TPA-induced transformation without significantly affecting PKC activation, reactive oxygen species production, or c-jun induction, suggesting alternative mechanisms.
Conclusions:
- Phytopolyphenols, particularly those with specific hydroxyl group configurations and catechin structures, can inhibit TPA-induced cellular transformation.
- Inhibition of PKC activation, reactive oxygen species production, and c-jun induction are key but not the sole mechanisms by which these compounds exert their anti-transformation effects.
- TPA may induce cellular transformation through pathways beyond PKC activation, reactive oxygen species, and c-jun induction.
More Related Videos
09:18Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
Published on: December 27, 2016
08:49Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries
Published on: January 22, 2019
