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Development and Maintenance of a Preclinical Patient Derived Tumor Xenograft Model for the Investigation of Novel Anti-Cancer Therapies
Published on: September 30, 2016
Enhanced chemosensitivity to CPT-11 in colorectal carcinoma xenografts by small hairpin RNA interference targeting
1State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No. 1, Gao-peng Street, Chengdu, Sichuan, 610041, China.
Abstract:
Commonly used drugs for the treatment of colon{} cancer patients like CPT-11 shows severe side effects or induces resistance in clinical settings. Thus, we analyzed a combination of PLK1 (polo-like kinase 1)-specific short hair RNA (shRNA), a potent tool to destroy mitosis in cancer cells, together with CPT-11 to enhance drug sensitivity. Cellular proliferation and apoptosis were determined in SW620 colorectal carcinoma cells. Knockdown of cellular PLK1 led to the decreased mRNA and PLK1 protein in RT-PCR and western blot assay. The viability declined (p<0.001) in MTT assay and colony formation assay, and the number of apoptotic cells was clearly increased (p<0.01) in flow cytometric analysis and Hoechst 33258 staining compared with control cells after incubation with PLK1-specific shRNA and SN-38. We found the level of cleaved PARP was also increased in vitro. In vivo, employment of shRNA targeting PLK1 improved the sensitivity to treat SW620 nude mouse model toward CPT-11. The combination therapy inhibited cellular proliferation and promoted apoptosis observed at the percentage of PCNA and caspase3 by immunohistochemistry, accompanied with TUNEL assay. As we expect, the combination treatment delayed tumor growth (p<0.01) and simultaneously reduced tumor weight (p<0.01) compared with control group. Taken together, combination of PLK1-specific shRNA interference with low-dose CPT-11 triggered a antitumor efficacy and represented a potential strategy to treat colon cancer.
Insights
Combining polo-like kinase 1 (PLK1)-specific short hair RNA (shRNA) with CPT-11 chemotherapy effectively combats colon cancer. This novel approach enhances drug sensitivity, reduces tumor growth, and promotes cancer cell death in preclinical models.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Therapeutics
Background:
- Standard colon cancer treatments like CPT-11 often cause severe side effects and drug resistance.
- Targeting polo-like kinase 1 (PLK1), crucial for mitosis, presents a potential strategy to overcome these limitations.
- Short hairpin RNA (shRNA) offers a precise method for gene knockdown, including PLK1.
Purpose of the Study:
- To investigate the synergistic antitumor effects of combining PLK1-specific shRNA with CPT-11 in colon cancer.
- To evaluate the impact of this combination therapy on cancer cell proliferation, apoptosis, and drug sensitivity.
- To assess the efficacy of PLK1-shRNA and CPT-11 combination in a preclinical mouse model of colon cancer.
Main Methods:
- SW620 colorectal carcinoma cells were treated with PLK1-specific shRNA and SN-38 (active metabolite of CPT-11).
- Cellular proliferation and apoptosis were assessed using MTT assays, colony formation assays, flow cytometry, and Hoechst staining.
- In vivo studies involved a SW620 nude mouse model treated with the combination therapy, with tumor growth and weight monitored.
Main Results:
- PLK1 knockdown significantly reduced SW620 cell viability and colony formation while increasing apoptosis.
- The combination therapy demonstrated enhanced antitumor efficacy in vivo, significantly delaying tumor growth and reducing tumor weight.
- Biomarkers of proliferation (PCNA) and apoptosis (caspase3, cleaved PARP) were modulated favorably by the combination treatment.
Conclusions:
- The combination of PLK1-specific shRNA interference and low-dose CPT-11 exhibits significant antitumor efficacy against colon cancer.
- This strategy enhances sensitivity to CPT-11, reduces tumor progression, and promotes cancer cell apoptosis.
- Combining PLK1-targeted shRNA with CPT-11 represents a promising therapeutic approach for colon cancer treatment.
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