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Mutated ras p21 as a target for cancer therapy in mouse transitional cell carcinoma
1Division of Urology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
Purpose:
To establish an experimental mouse model for bladder cancer immunotherapy using mutated ras as a target.
Materials And Methods:
A tumorigenic mouse bladder transitional cell carcinoma (TCC) line MB49 (C57BL/6 origin) was analyzed for its c-ras gene status by DNA cloning and sequencing. Aberrant expression of the ras gene was measured with Western blotting. 13-mer peptides corresponding to residues 5 to 17 of the ras protein were synthesized and tested for immunogenicity in syngeneic C57BL/6 mice. Induction of specific immune responses was evaluated by analyzing splenocyte activity in vitro and tumor suppression in vivo.
Results:
MB49 cells were found to contain a single amino acid substitution of serine for glycine at codon 12 in K-ras loci and an abundant amount of cellular mutated ras p21 protein. C57BL/6 mice immunized with the 13-mer serine-containing ras peptide exhibited mutation-specific immune responses in splenocyte proliferation, cytokine production and cytotoxicity. Specific antitumor immunity in the form of tumor growth delay in vivo was observed in mice immunized with the same mutant peptide followed by subcutaneous MB49 tumor challenge and was enhanced by the addition of low dose interleukin-12.
Conclusions:
The mouse bladder TCC line MB49 contains a serine mutation at codon 12 of its K-ras gene that is sufficient to induce mutation-specific immune responses in vitro and specific protective immunity to MB49 tumor in vivo. Mutated oncoproteins may be ideal targets for the development of specific immunotherapy regimens for bladder cancer immunotherapy.
Insights
Researchers developed a mouse model for bladder cancer immunotherapy targeting mutated ras. Immunizing mice with a specific ras peptide induced immune responses and tumor suppression, showing potential for cancer treatment.
Area of Science:
- Oncology
- Immunology
- Molecular Biology
Background:
- Bladder cancer immunotherapy requires effective experimental models.
- Targeting oncogenic mutations like ras is a promising strategy.
Purpose of the Study:
- To create a mouse model for bladder cancer immunotherapy.
- To investigate the potential of mutated ras as a therapeutic target.
Main Methods:
- Analyzed MB49 mouse bladder cancer cells for ras gene mutations.
- Synthesized ras peptides and assessed immunogenicity in C57BL/6 mice.
- Evaluated immune responses and tumor suppression in vivo.
Main Results:
- MB49 cells harbor a K-ras mutation (glycine to serine at codon 12).
- Mice immunized with a mutant ras peptide showed mutation-specific immune responses.
- Tumor growth delay was observed in immunized mice, enhanced by interleukin-12.
Conclusions:
- The MB49 cell line with its K-ras mutation serves as a viable model for bladder cancer immunotherapy research.
- Mutated ras oncoproteins are suitable targets for developing specific immunotherapies for bladder cancer.