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Published on: July 28, 2012
Ki-67-directed antisense therapy in an orthotopic renal cell carcinoma model
1Department of Urology, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. IKausch@aol.com
Purpose:
The Ki-67 antigen is only present in proliferating cells. We have shown previously that phosphorothioate-modified antisense oligonucleotides (ON) against this antigen are potent antitumoral agents in bladder and prostate cancer-derived cells. Since ON are known to accumulate in vivo in the kidney, high local effectivity may be expected. Here, we evaluated and characterized antitumoral effects in an orthotopic renal cell cancer (RENCA) model.
Material And Methods:
RENCA cells were incubated with antisense and control ON in the presence of a cationic lipid. Uptake studies were performed with FITC-labeled ON. Ki-67 protein analysis after ON treatment was performed by immunohistochemical staining. For animal studies, 1 x 10(5) RENCA cells were implanted under the renal capsule of Balb/c mice. Antisense and control ON were injected intraperitoneally daily for 14 days. Tumor weights and status of metastasis were documented after sacrifice. Furthermore, vessel density in tumor tissues was determined by CD31 immunolabeling.
Results:
Antisense treatment of RENCA cells resulted in specific reduction of the Ki-67 protein and inhibition of cell growth. A substantial cellular uptake of labeled ON was noted in vitro and in vivo. The growth of orthotopically implantated syngeneic kidney tumors in immunocompetent mice was significantly inhibited in antisense-treated animals (p < 0.05). Furthermore, lung metastases were noted in 10% of antisense-treated animals compared to 30-40% in control groups. Immunohistochemical staining of the vessel density showed no significant difference among treatment groups.
Conclusions:
The results demonstrate that Ki-67-directed antisense oligonucleotides are potent inhibitors of target protein expression and proliferation of tumor cells in vitro, and of tumor growth and lung metastasis formation in murine renal cell carcinoma whereas tumor vascularization is not significantly affected.
Insights
Antisense oligonucleotides targeting Ki-67 significantly inhibited renal cell carcinoma (RENCA) growth and metastasis in mice. This targeted therapy reduced tumor cell proliferation and Ki-67 protein expression, showing promise for kidney cancer treatment.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- The Ki-67 antigen is a marker of cellular proliferation.
- Antisense oligonucleotides (ON) targeting Ki-67 have demonstrated antitumoral effects in bladder and prostate cancer cells.
- Oligonucleotides are known to accumulate in the kidney, suggesting potential for local therapeutic effects.
Purpose of the Study:
- To evaluate and characterize the antitumoral effects of Ki-67-directed antisense oligonucleotides in an orthotopic renal cell cancer (RENCA) model.
- To assess the impact of antisense ON on tumor growth, metastasis, and Ki-67 protein expression in vivo.
Main Methods:
- RENCA cells were treated with antisense and control ON in vitro and in vivo.
- Cellular uptake of fluorescently labeled ON was measured.
- Ki-67 protein levels were analyzed via immunohistochemistry.
- Antisense and control ON were administered to mice with orthotopically implanted RENCA tumors.
- Tumor weight, metastasis, and vessel density (CD31) were assessed post-treatment.
Main Results:
- Antisense ON treatment specifically reduced Ki-67 protein expression and inhibited RENCA cell growth in vitro.
- Significant inhibition of orthotopic kidney tumor growth was observed in antisense-treated mice (p < 0.05).
- Lung metastasis incidence was lower in antisense-treated animals (10%) compared to controls (30-40%).
- No significant difference in tumor vessel density was found among treatment groups.
Conclusions:
- Ki-67-directed antisense oligonucleotides effectively inhibit target protein expression and tumor cell proliferation in vitro.
- Antisense ON demonstrated potent inhibition of tumor growth and lung metastasis in a murine renal cell carcinoma model.
- Tumor vascularization was not significantly affected by the antisense oligonucleotide treatment.
