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Antiproliferative effect of DNA polymerase alpha antisense oligodeoxynucleotides on breast cancer cells
A Alama1, R Meazza, F Barbieri
1Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy.
Abstract:
Antisense oligonucleotides appear to offer considerable promise as sequence-specific inhibitors of gene expression. Different cellular targets for oligodeoxynucleotides with oncologic interest have been identified such as oncogenes, growth factors, and cell cycle-related genes. DNA polymerase alpha (pol alpha) plays a relevant role in DNA synthesis and cell proliferation. Pol alpha gene expression is constitutive throughout the cell cycle and its mRNA content and activity are related to the growth rate and neoplastic phenotype. The effects of a 18-mer pol alpha antisense oligomer on the proliferation of the MDA-MB 231 breast cancer cell line have been investigated. After 48 h in culture with oligomers (10 microM), about 50% growth inhibition was observed in antisense-treated cells, as evaluated by 3-(4,5-dimethythiazol-2yl)-2,5-diphenyltetrazolium bromide assay and cell count. [3H]Thymidine incorporation exhibited a 90% inhibition of DNA synthesis associated to 64% accumulation of cells at the G1-S border of the cycle as by flow cytometry, at 24 h. Northern hybridization and SDS-PAGE of immunoprecipitated MDA-MB 231 cell lysates revealed a decreased expression of pol alpha mRNA and a reduction of the 180-kDa polypeptide, respectively. Collectively, the data further confirm the relevance of pol alpha in the replicative cycle, as well as strengthen the potentiality of the antisense strategy for the control of gene expression and cell growth.
Insights
Antisense oligonucleotides targeting DNA polymerase alpha (pol alpha) significantly inhibited breast cancer cell proliferation. This approach reduced DNA synthesis and cell growth, highlighting its potential for cancer therapy.
Area of Science:
- Molecular Biology
- Cancer Research
- Oligonucleotide Therapeutics
Background:
- Antisense oligonucleotides are promising sequence-specific gene expression inhibitors.
- DNA polymerase alpha (pol alpha) is crucial for DNA synthesis and cell proliferation, with elevated expression in cancer.
Purpose of the Study:
- To investigate the effect of a pol alpha antisense oligomer on MDA-MB 231 breast cancer cell line proliferation.
- To evaluate the potential of antisense strategy for controlling gene expression and cell growth in cancer.
Main Methods:
- Treatment of MDA-MB 231 cells with a pol alpha antisense oligomer.
- Assessing cell proliferation using MTT assay and cell counting.
- Measuring DNA synthesis via [3H]thymidine incorporation and cell cycle distribution by flow cytometry.
- Analyzing pol alpha mRNA and protein expression using Northern hybridization and SDS-PAGE.
Main Results:
- A 50% inhibition of cell growth was observed after 48 hours of antisense treatment.
- A 90% inhibition of DNA synthesis and 64% G1-S phase cell cycle arrest occurred within 24 hours.
- Decreased pol alpha mRNA and protein levels were detected in treated cells.
Conclusions:
- Pol alpha plays a critical role in the cell replicative cycle.
- Antisense strategy targeting pol alpha demonstrates significant potential for controlling cancer cell gene expression and growth.