Isoprenylcysteine carboxylmethyltransferase is critical for malignant transformation and tumor maintenance by all RAS...

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• Direct RAS inhibitors have shown limited success.
• Isoprenylcysteine carboxylmethyltransferase (ICMT) is crucial for RAS post-translational modification.
• Genetic evidence for ICMT's role in RAS-driven human cancers is lacking.

Purpose of the Study:

• To investigate the role of ICMT in RAS-driven human cancer initiation and maintenance.
• To establish direct genetic evidence for ICMT's function in cancer.

Main Methods:

• CRISPR/Cas9 genome editing was used to create isogenic cell lines with ICMT loss-of-function.
• Studies included RAS-transformed human mammary epithelial cells (HME1) and human cancer cell lines (MiaPaca-2, MDA-MB-231) with mutant KRAS.
• In vitro and in vivo tumorigenesis assays were performed.

Main Results:

• ICMT loss-of-function abolished tumor initiation by mutant RAS isoforms in HME1 cells.
• ICMT loss-of-function eliminated the tumor maintenance capacity of MiaPaca-2 and MDA-MB-231 cells.
• These findings demonstrate ICMT's critical role in RAS-driven cancers.

Conclusions:

• ICMT is essential for both the initiation and maintenance of RAS-driven human cancers.
• Targeting ICMT represents a promising therapeutic strategy for RAS-driven malignancies.
• This study provides direct genetic evidence for ICMT's critical role in oncogenesis.