Non-invasive in vivo imaging of early metabolic tumor response to therapies targeting choline metabolism.

Abstract

The cholinic phenotype, characterized by elevated phosphocholine and a high production of total-choline (tCho)-containing metabolites, is a metabolic hallmark of cancer. It can be exploited for targeted therapy. Non-invasive imaging biomarkers are required to evaluate an individual's response to targeted anticancer agents that usually do not rapidly cause tumor shrinkage. Because metabolic changes can manifest at earlier stages of therapy than changes in tumor size, the aim of the current study was to evaluate (1)H-MRS and diffusion-weighted MRI (DW-MRI) as markers of tumor response to the modulation of the choline pathway in mammary tumor xenografts. Inhibition of choline kinase activity was achieved with the direct pharmacological inhibitor H-89, indirect inhibitor sorafenib and down-regulation of choline-kinase α (ChKA) expression using specific short-hairpin RNA (shRNA). While all three strategies significantly decreased tCho tumor content in vivo, only sorafenib and anti-ChKA shRNA significantly repressed tumor growth. The increase of apparent-diffusion-coefficient of water (ADCw) measured by DW-MRI, was predictive of the induced necrosis and inhibition of the tumor growth in sorafenib treated mice, while the absence of change in ADC values in H89 treated mice predicted the absence of effect in terms of tumor necrosis and tumor growth. In conclusion, (1)H-choline spectroscopy can be useful as a pharmacodynamic biomarker for choline targeted agents, while DW-MRI can be used as an early marker of effective tumor response to choline targeted therapies. DW-MRI combined to choline spectroscopy may provide a useful non-invasive marker for the early clinical assessment of tumor response to therapies targeting choline signaling.

• Authors: Lionel Mignion, Pierre Danhier, Julie Magat, Paolo E Porporato, Julien Masquelier, Vincent Gregoire, Giulio G Muccioli, Pierre Sonveaux, Bernard Gallez, Bénédicte F Jordan
• Journal: International journal of cancer (Int J Cancer) Vol. 138 Issue 8 Pg. 2043-9 (Apr 15 2016) ISSN: 1097-0215 [Electronic] United States
• PMID: 26595604 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 UICC.

Chemical References

• Antineoplastic Agents
• Isoquinolines
• Phenylurea Compounds
• Protein Kinase Inhibitors
• Protons
• Sulfonamides
• Niacinamide
• Sorafenib
• Choline Kinase
• N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide

Topics

• Animals
• Antineoplastic Agents (pharmacology)
• Choline Kinase (antagonists & inhibitors)
• Diffusion Magnetic Resonance Imaging (methods)
• Female
• Heterografts
• Humans
• Isoquinolines (pharmacology)
• Magnetic Resonance Spectroscopy (methods)
• Mammary Neoplasms, Experimental (drug therapy, metabolism, pathology)
• Mice
• Niacinamide (analogs & derivatives, pharmacology)
• Phenylurea Compounds (pharmacology)
• Protein Kinase Inhibitors (pharmacology)
• Protons
• Sorafenib
• Sulfonamides (pharmacology)