TYMS promotes genomic instability and tumor progression in Ink4a/Arf null background

Area of Science:

• Oncology
• Cancer Biology
• Genetics

Background:

• Elevated thymidylate synthase (TYMS) expression is linked to oncogenesis and tumorigenesis.
• Loss of Ink4a/Arf is a frequent somatic mutation in human cancers.
• Understanding gene cooperation in cancer development is crucial.

Purpose of the Study:

• To investigate the cooperative effect of ectopic human TYMS expression and Ink4a/Arf loss on tumorigenesis.
• To determine the impact of this cooperation on tumor progression, metastasis, and genomic stability.
• To evaluate the therapeutic potential of targeting TYMS in this context.

Main Methods:

• Utilized a genetically engineered mouse model with human TYMS and Ink4a/Arf deficiency (hTS/Ink4a/Arf ^-/-).
• Assessed tumor incidence, progression, metastasis, and survival rates.
• Analyzed genomic instability markers, including DNA damage and aneuploidy.
• Investigated the effect of TYMS downregulation in vitro and in vivo using shRNA.

Main Results:

• Deregulated TYMS expression in an Ink4a/Arf null background accelerated tumorigenesis and metastasis.
• Tumors exhibited genomic instability, increased DNA damage, aneuploidy, and G1/S checkpoint loss.
• In vitro TYMS downregulation reduced proliferation and sensitized cells to chemotherapy.
• In vivo TYMS depletion reduced tumor incidence, delayed progression, and prolonged survival.

Conclusions:

• Cooperation between TYMS activation and Ink4a/Arf loss enhances uncontrolled cell proliferation and tumor growth.
• Targeting TYMS is a promising strategy to delay tumorigenesis and prolong survival in relevant cancer contexts.
• This study highlights the importance of targeting specific genetic interactions in cancer therapy.