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Involvement of the DNA mismatch repair system in antineoplastic drug resistance
1Humboldt-University Berlin, University Hospital Charité Campus Mitte, Institute of Pathology, Germany. hermann.lage@charite.de
Abstract:
Different types of antineoplastic drugs, such as the alkylating agents busulfan, N-methyl-N'-nitro-N-nitrosoguanidine, N-methyl-N-nitrosourea, procarbazine and temozolomide, the antimetabolites, mercaptopurine and 6-thioguanine, the platinum compounds carboplatin and cisplatin, the anthracycline doxorubicin and the epipodophyllotoxine etoposide act by damaging DNA directly or indirectly. Increasing evidence has shown that tumours could acquire resistance to these drugs by loss of DNA-mismatch repair (MMR) activity. This phenomenon is caused by a decreased MMR-dependent stimulation of signal-transduction pathways causing programmed cell death. Simultaneously, the mutation rate in MMR-deficient tumours is increasing, which could lead to additional secondary drug/resistance phenotypes to other antineoplastic agents. In addition to this, an enhanced mutation rate may contribute to increased phenotypic variation and therefore the clinical aggressiveness of primary tumours and their metastases.
Insights
Tumors can resist antineoplastic drugs by losing DNA-mismatch repair (MMR) activity. This loss increases mutation rates, potentially driving tumor aggressiveness and resistance to further treatments.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Antineoplastic drugs damage DNA to inhibit tumor growth.
- Tumor resistance to these drugs is a significant clinical challenge.
Purpose of the Study:
- To investigate the role of DNA-mismatch repair (MMR) deficiency in acquired resistance to antineoplastic agents.
- To explore the consequences of MMR deficiency on tumor mutation rates and clinical behavior.
Main Methods:
- The study reviews evidence linking MMR activity to drug-induced DNA damage and programmed cell death.
- Analysis of mutation rates in MMR-deficient tumors and their potential impact on drug resistance phenotypes.
Main Results:
- Loss of MMR activity confers resistance to various antineoplastic drugs, including alkylating agents, antimetabolites, and platinum compounds.
- MMR deficiency leads to a significantly increased mutation rate in tumor cells.
- This enhanced mutation rate can result in secondary drug resistance and increased tumor aggressiveness.
Conclusions:
- MMR deficiency is a key mechanism for acquired resistance to DNA-damaging antineoplastic drugs.
- Increased mutation rates in MMR-deficient tumors contribute to therapeutic challenges and potentially poorer clinical outcomes.