IHC examination confirmed a marked EGFR silencing efficiency of the LPEI siRNA EGFR complexes. Volasertib msds These results suggested that EGFR specific siRNA complexed with LPEI could ef ficiently reduce EGFR expression at both mRNA and pro tein levels in SPC A1 xenografted tumors, with no non specific RNAi effect being observed. LPEI siRNA EGFR complexes inhibit tumor growth following repeated i. p. administration Previously we demonstrated that stable downregulation of EGFR expression by vector based shRNA significantly inhibited NSCLC cells proliferation. Therefore, we used the athymic nude mouse model to test if repeated systemic administration of LPEI complexed and EGFR specific siRNA could result in growth inhibition of SPC A1 xenografted tumors. Mice were grouped and treated as described above.

As shown in Figure 3A, tumors in mice treated with LPEI complexed non specific siRNA grew similar to those of GS treated mice and followed for 2 weeks. Nonetheless, there was no significance dif ference. However, treatment with EGFR specific Inhibitors,Modulators,Libraries siRNA vectored by LPEI induced significant tumor growth inhibition. Differences reached statistical significance at day 10, and tumor weight reduction at day 22 was almost 50%. Also, tumor IHC revealed a marked downregulation of EGFR protein expression in the LPEI siRNA EGFR treated group, Inhibitors,Modulators,Libraries and, as shown by western blot analysis, inhibitory efficiency was 55%. To identify tumor proliferation and apoptosis following i. p. injections with LPEI complexed EGFR specific siRNA, we also examined PCNA expression and apoptosis induced DNA fragmentation in mice xenografts.

As shown, in the LPEI siRNA EGFR treated group, Inhibitors,Modulators,Libraries PCNA positive Inhibitors,Modulators,Libraries staining was reduced, while TUNEL positive cell counts were significantly higher than in the other two groups. Comparisons between the three groups revealed a 30% descent in the proliferation index, as well as a twofold in crement in the apoptosis index under LPEI complexed EGFR specific siRNA treatment. In contrast, no significant difference was found in cell proliferation or apoptosis between LPEI siRNA NEG and GS treated groups. These results provide evidence that the observed inhibitory effect on tumor growth was based on specific EGFR down regulation, acting through modulations of cell proliferation and apoptosis.

Toxicity To determine whether following repeated systemic ad ministration with the LPEI siRNA Inhibitors,Modulators,Libraries EGFR complexes there could be organ toxicity, mice blood levels of ALT and AST, urea and creatinine were Dorsomorphin measured. As shown in Table 2, there was no evidence of increased liver toxicity or significance renal toxicity. In addition, micro scopically, there was neither necrosis nor inflammatory cell infiltration of the heart, liver, lungs, or kidneys. These results suggest that the therapy of repeated i. p. administration with 0. 6 nmol EGFR specific siRNA vectored by LPEI does not induce organ toxicity in SPC A1 xenografted mice.