CBP-501 Acetate – Calmodulin-Binding Peptide and G2 Checkpoint Inhibitor

Description

Product Description

CBP-501 acetate is a synthetic calmodulin-binding peptide with significant potential as a G2 checkpoint abrogating anticancer agent. It functions by inhibiting multiple Ser216-specific kinases that regulate cell cycle progression, particularly at the G2/M checkpoint. This makes it a valuable research compound for studying cell cycle regulation, DNA damage responses, and chemosensitization mechanisms in cancer biology.

Background and Development

Cell cycle checkpoints serve as critical control mechanisms that ensure accurate DNA replication and chromosome segregation. The G2/M checkpoint specifically prevents cells with damaged DNA from entering mitosis, allowing time for repair. Many tumors exploit this mechanism to resist DNA-damaging chemotherapeutic agents.

CBP-501 acetate was developed to override the G2 arrest, forcing damaged tumor cells into mitosis before repair can occur, ultimately triggering apoptosis. The compound exhibits broad inhibitory activity against Ser216-specific kinases, such as:

• MAPKAP-K2 (IC₅₀ = 0.9 μM)

• C-Tak1 (IC₅₀ = 1.4 μM)

• CHK1 (IC₅₀ = 3.4 μM)

• CHK2 (IC₅₀ = 6.5 μM)

These kinases play key roles in checkpoint signaling and DNA repair. By blocking their activity, CBP-501 acetate reduces phosphorylation of Cdc25C at Ser216, thereby reactivating the phosphatase and promoting entry into mitosis.

Anticancer Research Applications

CBP-501 acetate enhances the cytotoxicity of agents such as cisplatin, etoposide, and doxorubicin by preventing G2 arrest and promoting apoptosis in damaged cells. This synergy makes it a valuable tool for combination therapy studies in:

• Lung cancer

• Colorectal carcinoma

• Ovarian cancer

• Pancreatic cancer

• Prostate and bladder cancers

It is also widely used for mechanistic studies of calmodulin-dependent signal transduction, kinase inhibition profiling, and DNA damage checkpoint regulation.

Key Features

• Calmodulin-binding, cell-permeable peptide

• Potent inhibitor of multiple Ser216-specific kinases

• G2 checkpoint abrogator

• Enhances chemosensitivity of tumor cells

• Suitable for molecular oncology and signal transduction research

Product Specifications

Mechanism of Action

CBP-501 acetate exerts its biological activity through calmodulin binding and kinase inhibition, leading to G2 checkpoint abrogation and enhanced chemosensitivity.

1. Calmodulin Binding and Signal Modulation

Calmodulin (CaM) is a calcium-binding messenger protein that regulates numerous kinases and phosphatases. CBP-501 acetate interacts directly with calmodulin, altering its conformation and interfering with Ca²⁺/CaM-dependent kinase signaling.

This binding disrupts the regulation of downstream targets involved in DNA repair and stress response, including CHK1, CHK2, and C-Tak1.

2. Inhibition of Ser216-Specific Kinases

CBP-501 acetate selectively inhibits kinases that phosphorylate Cdc25C at Ser216, a modification that keeps the phosphatase inactive and halts the cell cycle in G2. By preventing this phosphorylation, CBP-501 restores Cdc25C activity, reactivates Cdc2/cyclin B complex, and drives cells into mitosis.

This process leads to premature mitotic entry, resulting in mitotic catastrophe in DNA-damaged cells.

3. G2 Checkpoint Abrogation and Chemosensitization

Tumor cells often exploit G2 arrest to survive after chemotherapy. CBP-501 acetate forces these cells through the checkpoint, rendering them vulnerable to cytotoxic agents. In preclinical models, co-administration with cisplatin significantly increased tumor regression rates.

4. Calmodulin-Dependent Kinase Regulation

Beyond checkpoint control, CBP-501 acetate modulates multiple CaM-dependent enzymes that contribute to cell cycle regulation, stress response, and apoptosis. This pleiotropic activity makes it a powerful experimental tool for dissecting Ca²⁺-mediated signaling networks.

Side Effects

In preclinical and cellular studies, the following effects have been observed:

• Cellular Cytotoxicity: Concentration-dependent apoptosis in dividing cells.

• Cell Cycle Perturbation: G2/M transition deregulation leading to mitotic catastrophe.

• DNA Damage Sensitization: Enhanced sensitivity to platinum-based drugs.

• Mild Off-target Effects: Potential interference with other calmodulin-dependent enzymes.

• In Vivo Observations: Transient hepatotoxicity and altered calcium signaling at high doses.

Proper handling, dilution, and experimental calibration are essential for reproducible and safe results.

Disclaimer

For research use only. Not intended for human or veterinary use, diagnosis, or treatment.

Keywords

CBP-501 acetate, calmodulin-binding peptide, G2 checkpoint inhibitor, Ser216 kinase inhibitor, MAPKAP-K2 inhibitor, C-Tak1 inhibitor, CHK1 inhibitor, CHK2 inhibitor, cell cycle regulator, chemosensitizer, anticancer research compound.Peptide Manufacturer-Wholesaler

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