Presentation Authors: Mariela Araya, Santiago , Chile, Francisca Guevara, Jaime Villegas, Luis Alarcón, Luis Burzio, Vincenzo Borgna*, Santiago, Chile
Introduction: Renal cell carcinoma (RCC) is the seventh most common cancer in men. Patients with distant metastasis have a 5 year survival rate of < 10%. Metastatic RCC is resistant to chemotherapy and radiotherapy, so treatments are focused on targeted therapies. We previously described components of a unique family of non-coding mitocondrial transcripts named ASncmtRNAs. These transcripts are expressed in normal proliferating cells, but are down-regulated in tumor cells of different origin._x000D_
We found that knocking down these transcripts in vitro with antisense oligonucleotide (ASO) induces selective death of several human and murine tumor cell lines without affecting viability of normal cells. The aim of this study was to evaluate in vitro and in vivo, the therapeutic value of silencing the ASncmtRNA with ASO in human cell lines/primary cultures and in A498 xenograft and Patient derived xenograft (PDX) RCC model.
Methods: For the in vitro studies we used different human renal carcinoma cell lines (786-O, Caki-1, A498) and 6 primary cultures derived from RCC patients. Knock down of the ASncmtRNA was achieved by transfection of ASO targeted to the loop region of these transcripts (Andes-1537). As control, we used ASO with unrelated sequence (NR-ASO). Cell death was evaluated with FACS by PI and tripan exclusion assay and the decrease in tumorigenicity was determined by sphere assay. The apoptosis hallmarks evaluated were Caspase activation, DNA fragmentation and phosphatidylserine exposure on the outer membrane. For the in vivo model 2,5x106 A498 cells were implanted subcutaneous in 10 NOD/SCID Balb/c mice. I. For the PDX mordel a 5mm3 tissue sample from a pT2N0M0 ISUP 3 RCC patient was implanted subcutaneosly in 10 NOD/SCID Balb/c micentraperitoneal treatments were performed every 48 hours for 6 times with Andes-1537 and NR-ASO (10 mg / kg). Necropsies were performed when the tumor reach 1000mm3
Results: In vitro Andes-1537 treatment induces massive cell death by apoptosis (70-80%) at 48 hrs post-treatment. A significant inhibition of spheres was also observed.In the A498 model the decrease in tumor growth was statistically significant in mice treated with Andes-1537 in comparison with NR-ASO (p. < 0.05), in the PDX model the mean volume in the control group at 60 days was 1000mm3 and in Andes-1537 160mm3
Conclusions: These results support the potential use of Andes-1537 as a novel therapy for RCC.