p16 expression confers sensitivity to CDK2 inhibitors
Abstract:
Blocking the cell cycle is a promising avenue for cancer therapy, with Cyclin-Dependent Kinase 2 (CDK2) emerging as a key target. However, in multiple cell types, CDK4/6 activity compensates for CDK2 inhibition and sustains the proliferative program, enabling CDK2 reactivation. Thus, we hypothesized that sensitivity to CDK2 inhibition is linked to the absence of this CDK4/6-mediated compensatory mechanism. Here we show that Cyclin E1-driven ovarian cancers often co-express the tumor suppressor p16, which inhibits CDK4/6. We show that ovarian cancer cells expressing p16 exhibit heightened sensitivity to CDK2 inhibitors and that depletion of p16 renders them significantly more resistant. Multiplexed immunofluorescence of 225 ovarian patient tumors reveals that at least 18% of tumors express high Cyclin E1 and high p16, a group that we expect to be particularly sensitive to CDK2 inhibition. Thus, p16 may be a useful biomarker for identifying the patients most likely to benefit from CDK2 inhibitors.
Insights
The tumor suppressor p16 inhibits CDK4/6, enhancing sensitivity to CDK2 inhibitors in ovarian cancers. This finding identifies p16 as a potential biomarker for predicting patient response to CDK2-targeted cancer therapy.
Area of Science:
- Oncology
- Molecular Biology
- Cell Cycle Regulation
Background:
- Cyclin-Dependent Kinase 2 (CDK2) is a key target for cancer therapy, but its inhibition can be circumvented by compensatory CDK4/6 activity.
- This compensatory mechanism allows cancer cells to maintain proliferation and CDK2 reactivation, limiting the efficacy of CDK2 inhibitors.
Purpose of the Study:
- To investigate the hypothesis that sensitivity to CDK2 inhibition is associated with the absence of CDK4/6-mediated compensation.
- To identify potential biomarkers for predicting patient response to CDK2 inhibitors in ovarian cancer.
Main Methods:
- Analysis of ovarian cancer cell lines co-expressing Cyclin E1 and the tumor suppressor p16.
- Assessment of sensitivity to CDK2 inhibitors in cells with and without p16.
- Multiplexed immunofluorescence staining of 225 ovarian patient tumors to evaluate Cyclin E1 and p16 expression levels.
Main Results:
- Ovarian cancer cells expressing p16 demonstrated heightened sensitivity to CDK2 inhibitors.
- Depletion of p16 significantly increased resistance to CDK2 inhibitors.
- At least 18% of analyzed ovarian tumors showed high expression of both Cyclin E1 and p16.
Conclusions:
- The presence of p16, which inhibits CDK4/6, is linked to increased sensitivity to CDK2 inhibitors in ovarian cancer.
- p16 may serve as a predictive biomarker for identifying ovarian cancer patients who will benefit from CDK2 inhibitor therapy.
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