Evaluation of tankyrase inhibition in whole cells
Tomokazu Ohishi1, Takashi Tsuruo, Hiroyuki Seimiya
1Division of Molecular Biotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan.
Abstract:
The telomeric poly(ADP-ribose) polymerase (PARP), tankyrase 1, modulates the impact of telomerase inhibition on human cancer cells. Thus, overexpression of tankyrase 1 in telomerase-positive cancer cells confers resistance to telomerase inhibitors, such as MST-312, whereas pharmacological inhibition of tankyrase 1 enhances telomere shortening by MST-312. These facts indicate that tankyrase 1 could be a target for telomere-directed molecular cancer therapy. Here, the authors describe a convenient method to monitor the telomeric function of tankyrase 1. This protocol takes much less time than the telomere Southern blot analysis and can be utilized as a rapid screening system for tankyrase 1 inhibitors that are effective in intact cells. For direct monitoring of tankyrase 1 PARP activity, a protocol for the in vitro enzyme assay is also described.
Insights
Tankyrase 1, a telomeric enzyme, plays a key role in cancer cell resistance to telomerase inhibitors. Targeting tankyrase 1 offers a new strategy for telomere-directed cancer therapy.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Telomeric poly(ADP-ribose) polymerase (PARP), specifically tankyrase 1, influences cancer cell response to telomerase inhibition.
- Overexpression of tankyrase 1 in telomerase-positive cancer cells leads to resistance against telomerase inhibitors like MST-312.
Purpose of the Study:
- To establish a convenient and rapid method for monitoring the telomeric function of tankyrase 1.
- To develop a screening system for identifying effective tankyrase 1 inhibitors in intact cells.
- To describe an in vitro enzyme assay for direct monitoring of tankyrase 1 PARP activity.
Main Methods:
- Development of a novel protocol to assess tankyrase 1's telomeric function.
- Utilizing the developed protocol as a rapid screening system for tankyrase 1 inhibitors.
- Establishing an in vitro enzyme assay for direct measurement of tankyrase 1 poly(ADP-ribose) polymerase activity.
Main Results:
- The new protocol is significantly faster than traditional telomere Southern blot analysis.
- The method allows for effective screening of tankyrase 1 inhibitors in intact cancer cells.
- An in vitro assay provides a direct measure of tankyrase 1's enzymatic activity.
Conclusions:
- Tankyrase 1 is a potential therapeutic target for telomere-directed cancer therapy.
- The developed methods offer efficient tools for studying tankyrase 1 function and for drug discovery.
