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Updated: Aug 12, 2026
Modeling Chemotherapy Resistant Leukemia In Vitro
Published on: February 9, 2016
In vitro sensitivity of T-cell lymphoblastic leukemia to UCN-01 (7-hydroxystaurosporine) is dependent on p16 protein
M Omura-Minamisawa1, M B Diccianni, A Batova
1Department of Pediatrics/Hematology-Oncology, University of California, San Diego 92103-8447, USA.
Abstract:
p16 regulates the cell cycle pathway by inhibiting the cyclin Ds-cyclin-dependent kinase (CDK) 4/6-mediated phosphorylation of retinoblastoma protein (pRb). Previously, we reported that most primary T-cell acute lymphoblastic leukemia (T-ALL) harbored p16 inactivation and hyperphosphorylated pRb without cyclin Ds or CDK4/6 alterations. Therefore, inhibiting CDK4/6 may be an ideal therapeutic approach for p16 (-) T-ALL. UCN-01 (7-hydroxystaurosporine) is a potent antitumor agent that exerts its effects through the inhibition of CDKs. We now report that p16 protein expression status of T-ALL cells influences their sensitivity to UCN-01. In 36 primary T-ALL cells, the IC50s of UCN-01 in the 27 p16 (-) cells (43+/-52 nM) was significantly lower than that in the 9 p16 (+) cells (258+/-260 nM). Our results suggest that agents like UCN-01 may be useful as a p16-selective therapy for T-ALL.
Insights
p16-negative T-cell acute lymphoblastic leukemia (T-ALL) cells are more sensitive to UCN-01, a cyclin-dependent kinase (CDK) inhibitor. This suggests UCN-01 could be a targeted therapy for T-ALL lacking p16 expression.
Area of Science:
- Oncology
- Molecular Biology
- Cell Cycle Regulation
Background:
- p16 protein is crucial for cell cycle regulation by inhibiting cyclin D-CDK4/6-mediated phosphorylation of retinoblastoma protein (pRb).
- Most T-cell acute lymphoblastic leukemia (T-ALL) cases exhibit p16 inactivation and pRb hyperphosphorylation without alterations in cyclin D or CDK4/6.
- CDK4/6 inhibition presents a potential therapeutic strategy for p16-negative T-ALL.
Purpose of the Study:
- To investigate the influence of p16 protein expression on T-ALL cell sensitivity to UCN-01, a CDK inhibitor.
- To evaluate UCN-01 as a potential p16-selective therapy for T-ALL.
Main Methods:
- Assessed p16 protein expression status in 36 primary T-ALL cells.
- Determined the half-maximal inhibitory concentration (IC50) of UCN-01 in p16-negative and p16-positive T-ALL cells.
- Compared UCN-01 sensitivity based on p16 expression levels.
Main Results:
- UCN-01 exhibited significantly lower IC50 values in p16-negative T-ALL cells (43+/-52 nM) compared to p16-positive cells (258+/-260 nM).
- A notable difference in sensitivity to UCN-01 was observed between the two groups, with p16-negative cells being more susceptible.
Conclusions:
- T-ALL cell sensitivity to UCN-01 is influenced by p16 protein expression status.
- Agents like UCN-01 demonstrate potential as a p16-selective therapeutic approach for T-ALL.
