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Novel small interfering RNA cotargeting strategy as treatment for colorectal cancer
Joseph D Valentino1, Victoria A Elliott, Yekaterina Y Zaytseva
1Department of Surgery, University of Kentucky, Lexington, KY, USA.
Background:
RNA interference has the potential to be more selective than small molecule inhibitors and can be used to target proteins, such as Ras, that are currently undruggable. The purpose of our study was to determine the optimal cotargeting strategy of the commonly mutated PI3K/AKT/mTOR and Ras pathways by a selective RNA interference approach in colorectal cancer cell lines possessing coexistent PIK3CA and KRAS mutations.
Methods:
Human colorectal cancer cell lines HCT116 and DLD-1 were treated with a panel of small interfering RNAs directed against the PI3K/AKT/mTOR and Ras pathways; proliferation, apoptosis, and protein expression were assessed. Combined treatment with small interfering RNA and 5-fluorouracil was then evaluated.
Results:
PIK3CA and KRAS small interfering RNAs were most effective as single treatments; combined treatments with PIK3CA and KRAS small interfering RNA resulted in a more pronounced inhibition of colorectal cancer cell proliferation. Either KRAS small interfering RNA alone or combined PIK3CA and KRAS small interfering RNA treatments increased apoptosis in HCT116 cells but not in the DLD-1 cell line. Inhibition of 4E-BP1 phosphorylation correlated with increased apoptosis. In addition, small interfering RNA treatment combined with 5-fluorouracil further inhibited colorectal cancer cell proliferation.
Conclusion:
Combined PIK3CA and KRAS small interfering RNA treatments offer an effective therapy against colorectal cancer cells with coexisting mutations in both pathways. Decreased 4E-BP1 phosphorylation correlates with increased apoptosis and may provide a biomarker indicative of treatment success. In addition, small interfering RNA directed to PIK3CA and KRAS may be used to enhance the effects of current chemotherapy.
Insights
Targeting both PIK3CA and KRAS with RNA interference effectively inhibits colorectal cancer cell proliferation. This combined approach, along with 5-fluorouracil, shows promise for enhancing cancer therapy.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Genetics
Background:
- RNA interference (RNAi) offers a selective approach to target proteins, including currently undruggable ones like Ras.
- Colorectal cancer (CRC) often harbors mutations in both the PI3K/AKT/mTOR and Ras pathways.
- Investigating cotargeting strategies for these pathways is crucial for effective CRC treatment.
Purpose of the Study:
- To determine the optimal cotargeting strategy for the PI3K/AKT/mTOR and Ras pathways in colorectal cancer.
- To evaluate the efficacy of selective RNA interference in targeting coexistent PIK3CA and KRAS mutations in CRC cell lines.
Main Methods:
- Human CRC cell lines (HCT116, DLD-1) were treated with small interfering RNAs (siRNAs) against PI3K/AKT/mTOR and Ras pathways.
- Assessed were proliferation, apoptosis, and protein expression following siRNA treatments.
- Evaluated were combined treatments of siRNA with 5-fluorouracil.
Main Results:
- Single PIK3CA or KRAS siRNAs were effective, but combined PIK3CA and KRAS siRNAs showed more pronounced inhibition of CRC cell proliferation.
- KRAS siRNA alone or combined PIK3CA/KRAS siRNAs increased apoptosis in HCT116 cells.
- Inhibition of 4E-BP1 phosphorylation correlated with increased apoptosis, and siRNA combined with 5-fluorouracil further reduced proliferation.
Conclusions:
- Combined PIK3CA and KRAS siRNA treatments represent an effective therapy for CRC with coexisting mutations in these pathways.
- Decreased 4E-BP1 phosphorylation may serve as a biomarker for treatment success.
- RNAi targeting PIK3CA and KRAS can enhance the efficacy of existing chemotherapy.
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