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Updated: Sep 7, 2025
Live Imaging of Drug Responses in the Tumor Microenvironment in Mouse Models of Breast Cancer
Published on: March 24, 2013
In vivo visualization of fluorescence reflecting CDK4 activity in a breast cancer mouse model
Yi-Yang Gao1,2,3,4, Rui-Qin Yang1,2,3,4, Kang-Liang Lou1,2,3,4
1Department of Breast and Thyroid Surgery Xiang'an Hospital of Xiamen University, School of Medicine, Xiamen University Xiamen China.
Abstract:
The CDK4/6-Rb axis is a crucial target of cancer therapy and several selective inhibitors of it have been approved for clinical application. However, current therapeutic efficacy evaluation mostly relies on anatomical imaging, which cannot directly reflect changes in drug targets, leading to a delay in the selection of optimal treatment. In this study, we constructed a novel fluorescent probe, CPP30-Lipo/CDKACT4, for real-time monitoring of CDK4 activity and the therapeutic efficacy of its inhibitor in HR+/HER2- breast cancer. CPP30-Lipo/CDKACT4 exhibited good optical stability and targetability. The signal of the probe in living cells decreased after CDK4 knockdown or palbociclib treatment. Moreover, the fluorescence intensity of the tumors after 7 days of palbociclib treatment was significantly lower than that before treatment, while no significant change in tumor diameter was observed under magnetic resonance imaging. Overall, we developed an innovative fluorescent probe that can monitor CDK4 activity and the early therapeutic response to CDK4 inhibitors in living cells and in vivo. It may provide a new strategy for evaluating antitumor therapeutic efficacy in a clinical context and for drug development.
Insights
A new fluorescent probe monitors CDK4 activity, enabling early assessment of cancer drug effectiveness. This tool tracks CDK4 inhibitor response in breast cancer, outperforming traditional imaging for timely treatment adjustments.
Area of Science:
- Oncology
- Biomedical Imaging
- Drug Development
Background:
- The CDK4/6-Rb pathway is a key target in cancer therapy, with approved inhibitors available.
- Current efficacy assessments rely on anatomical imaging, which delays detection of treatment response at the molecular level.
Purpose of the Study:
- To develop a novel fluorescent probe for real-time monitoring of CDK4 activity.
- To evaluate the probe's utility in assessing therapeutic efficacy of CDK4 inhibitors in HR+/HER2- breast cancer.
Main Methods:
- Construction of a novel fluorescent probe, CPP30-Lipo/CDKACT4.
- Testing probe stability, targetability, and signal changes in cells and *in vivo* models after inhibitor treatment or gene knockdown.
- Comparison with magnetic resonance imaging for therapeutic response evaluation.
Main Results:
- CPP30-Lipo/CDKACT4 demonstrated good optical stability and target specificity.
- Probe signal decreased in cells with CDK4 knockdown or palbociclib treatment.
- Tumor fluorescence significantly decreased after 7 days of palbociclib, while tumor diameter showed no significant change via MRI.
Conclusions:
- An innovative fluorescent probe was developed for monitoring CDK4 activity and early response to CDK4 inhibitors.
- The probe offers a new strategy for evaluating antitumor therapeutic efficacy in preclinical models and potentially in clinical settings.
- This approach may accelerate drug development and optimize cancer treatment selection.
