Preclinical evaluation of the CDK4/6 inhibitor palbociclib in combination with a PI3K or MEK inhibitor in colorectal cancer.

Abstract

BACKGROUND:

Studies have demonstrated the efficacy of Palbociclib (CDK 4/6 inhibitor), Gedatolisib (PI3K/mTOR dual inhibitor) and PD0325901 (MEK1/2 inhibitor) in colorectal cancer (CRC), however single agent therapeutics are often limited by the development of resistance.

METHODS:

We compared the anti-proliferative effects of the combination of Gedatolisib and Palbociclib and Gedatolisib and PD0325901 in five CRC cell lines with varying mutational background and tested their combinations on total and phosphoprotein levels of signaling pathway proteins.

RESULTS:

The combination of Palbociclib and Gedatolisib was superior to the combination of Palbociclib and PD0325901. The combination of Palbociclib and Gedatolisib had synergistic anti-proliferative effects in all cell lines tested [CI range: 0.11-0.69] and resulted in the suppression of S6rp (S240/244), without AKT reactivation. The combination of Palbociclib and Gedatolisib increased BAX and Bcl-2 levels in PIK3CA mutated cell lines. The combination of Palbociclib and Gedatolisib caused MAPK/ERK reactivation, as seen by an increase in expression of total EGFR, regardless of the mutational status of the cells.

CONCLUSION:

This study shows that the combination of Palbociclib and Gedatolisib has synergistic anti-proliferative effects in both wild-type and mutated CRC cell lines. Separately, the phosphorylation of S6rp may be a promising biomarker of responsiveness to this combination.

• Authors: Cha Len Lee, Mattia Cremona, Angela Farrelly, Julie A Workman, Sean Kennedy, Razia Aslam, Aoife Carr, Stephen Madden, Brian O'Neill, Bryan T Hennessy, Sinead Toomey
• Journal: Cancer biology & therapy (Cancer Biol Ther) Vol. 24 Issue 1 Pg. 2223388 (12 31 2023) ISSN: 1555-8576 [Electronic] United States
• PMID: 37326340 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• mirdametinib
• palbociclib
• Phosphatidylinositol 3-Kinases
• Protein Kinase Inhibitors
• Phosphoinositide-3 Kinase Inhibitors
• Mitogen-Activated Protein Kinase Kinases
• CDK4 protein, human
• Cyclin-Dependent Kinase 4

Topics

• Humans
• Phosphatidylinositol 3-Kinases (metabolism)
• Cell Line, Tumor
• Protein Kinase Inhibitors (pharmacology, therapeutic use)
• Phosphoinositide-3 Kinase Inhibitors (pharmacology)
• Colorectal Neoplasms (drug therapy, genetics, metabolism)
• Mitogen-Activated Protein Kinase Kinases
• Cell Proliferation
• Cyclin-Dependent Kinase 4