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Utilizing Murine Inducible Telomerase Alleles in the Studies of Tissue Degeneration/Regeneration and Cancer
Published on: April 13, 2015
Synergistic tumor suppression by combined inhibition of telomerase and CDKN1A
Romi Gupta1, Yuying Dong1, Peter D Solomon1
1Departments of Pathology and.
Abstract:
Tumor suppressor p53 plays an important role in mediating growth inhibition upon telomere dysfunction. Here, we show that loss of the p53 target gene cyclin-dependent kinase inhibitor 1A (CDKN1A, also known as p21(WAF1/CIP1)) increases apoptosis induction following telomerase inhibition in a variety of cancer cell lines and mouse xenografts. This effect is highly specific to p21, as loss of other checkpoint proteins and CDK inhibitors did not affect apoptosis. In telomerase, inhibited cell loss of p21 leads to E2F1- and p53-mediated transcriptional activation of p53-upregulated modulator of apoptosis, resulting in increased apoptosis. Combined genetic or pharmacological inhibition of telomerase and p21 synergistically suppresses tumor growth. Furthermore, we demonstrate that simultaneous inhibition of telomerase and p21 also suppresses growth of tumors containing mutant p53 following pharmacological restoration of p53 activity. Collectively, our results establish that inactivation of p21 leads to increased apoptosis upon telomerase inhibition and thus identify a genetic vulnerability that can be exploited to treat many human cancers containing either wild-type or mutant p53.
Insights
Loss of p21 enhances cancer cell apoptosis after telomerase inhibition. Combining telomerase and p21 inhibition synergistically suppresses tumor growth, offering a new cancer treatment strategy.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Tumor suppressor p53 is crucial for inhibiting growth when telomeres are dysfunctional.
- Telomere dysfunction and p53 pathway are key in cancer development and progression.
Purpose of the Study:
- To investigate the role of p53 target gene CDKN1A (p21) in apoptosis following telomerase inhibition.
- To explore the therapeutic potential of combined telomerase and p21 inhibition in cancer treatment.
Main Methods:
- Utilized cancer cell lines and mouse xenografts to study apoptosis induction.
- Assessed the impact of genetic or pharmacological inhibition of telomerase and p21.
- Investigated p53-mediated transcriptional activation pathways.
Main Results:
- Loss of p21 specifically increased apoptosis upon telomerase inhibition, unlike other checkpoint proteins.
- p21 inactivation led to E2F1- and p53-mediated activation of PUMA, enhancing apoptosis.
- Combined inhibition of telomerase and p21 synergistically suppressed tumor growth in wild-type and mutant p53 models.
Conclusions:
- Inactivation of p21 sensitizes cancer cells to telomerase inhibition-induced apoptosis.
- Simultaneous inhibition of telomerase and p21 presents a promising therapeutic strategy for various human cancers, including those with mutant p53.
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