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Next-Generation CDK2/9 Inhibitors and Anaphase Catastrophe in Lung Cancer
Masanori Kawakami1, Lisa Maria Mustachio1, Jaime Rodriguez-Canales2
1Departments of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Background:
The first generation CDK2/7/9 inhibitor seliciclib (CYC202) causes multipolar anaphase and apoptosis in lung cancer cells with supernumerary centrosomes (known as anaphase catastrophe). We investigated a new and potent CDK2/9 inhibitor, CCT68127 (Cyclacel).
Methods:
CCT68127 was studied in lung cancer cells (three murine and five human) and control murine pulmonary epithelial and human immortalized bronchial epithelial cells. Robotic CCT68127 cell-based proliferation screens were used. Cells undergoing multipolar anaphase and inhibited centrosome clustering were scored. Reverse phase protein arrays (RPPAs) assessed CCT68127 effects on signaling pathways. The function of PEA15, a growth regulator highlighted by RPPAs, was analyzed. Syngeneic murine lung cancer xenografts (n = 4/group) determined CCT68127 effects on tumorigenicity and circulating tumor cell levels. All statistical tests were two-sided.
Results:
CCT68127 inhibited growth up to 88.5% (SD = 6.4%, P < .003) at 1 μM, induced apoptosis up to 42.6% (SD = 5.5%, P < .001) at 2 μM, and caused G1 or G2/M arrest in lung cancer cells with minimal effects on control cells (growth inhibition at 1 μM: 10.6%, SD = 3.6%, P = .32; apoptosis at 2 μM: 8.2%, SD = 1.0%, P = .22). A robotic screen found that lung cancer cells with KRAS mutation were particularly sensitive to CCT68127 ( P = .02 for IC 50 ). CCT68127 inhibited supernumerary centrosome clustering and caused anaphase catastrophe by 14.1% (SD = 3.6%, P < .009 at 1 μM). CCT68127 reduced PEA15 phosphorylation by 70% (SD = 3.0%, P = .003). The gain of PEA15 expression antagonized and its loss enhanced CCT68127-mediated growth inhibition. CCT68127 reduced lung cancer growth in vivo ( P < .001) and circulating tumor cells ( P = .004). Findings were confirmed with another CDK2/9 inhibitor, CYC065.
Conclusions:
Next-generation CDK2/9 inhibition elicits marked antineoplastic effects in lung cancer via anaphase catastrophe and reduced PEA15 phosphorylation.
Insights
A new CDK2/9 inhibitor, CCT68127, effectively targets lung cancer cells by inducing anaphase catastrophe and apoptosis. This potent compound shows promise in reducing tumor growth and circulating tumor cells.
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Seliciclib (CYC202), a first-generation CDK2/7/9 inhibitor, induces anaphase catastrophe and apoptosis in lung cancer cells with supernumerary centrosomes.
- CCT68127 is a novel and potent inhibitor of CDK2/9 investigated for its anti-cancer effects.
Purpose of the Study:
- To evaluate the efficacy of the CDK2/9 inhibitor CCT68127 in lung cancer cells.
- To investigate the mechanisms underlying CCT68127's anti-cancer activity, including effects on centrosome clustering, anaphase, apoptosis, and specific signaling pathways.
Main Methods:
- Cell-based proliferation screens were performed on murine and human lung cancer cells, as well as control epithelial cells.
- Robotic screening assessed CCT68127's impact on multipolar anaphase, centrosome clustering, and apoptosis.
- Reverse phase protein arrays (RPPAs) analyzed signaling pathway modulation, focusing on the growth regulator PEA15.
- In vivo studies using syngeneic murine lung cancer xenografts evaluated tumorigenicity and circulating tumor cell levels.
Main Results:
- CCT68127 significantly inhibited lung cancer cell growth (up to 88.5%) and induced apoptosis (up to 42.6%), with minimal effects on control cells.
- Lung cancer cells with KRAS mutations exhibited particular sensitivity to CCT68127.
- The inhibitor disrupted supernumerary centrosome clustering, leading to anaphase catastrophe, and reduced PEA15 phosphorylation.
- In vivo, CCT68127 suppressed tumor growth and decreased circulating tumor cells. Findings were corroborated using another CDK2/9 inhibitor, CYC065.
Conclusions:
- Next-generation CDK2/9 inhibition, exemplified by CCT68127, demonstrates significant antineoplastic effects in lung cancer.
- The mechanism involves inducing anaphase catastrophe through disrupted centrosome clustering and reduced PEA15 phosphorylation.
- CCT68127 represents a promising therapeutic strategy for lung cancer treatment.