3.3 Cell viability reduced by RS-NC-mediated siRNA delivery
The cancer growth-inhibiting (CGI) siRNAs were delivered via RS-NCs into MDA-MB-231 breast cancer cells. Reduced cell viabilities were measured using the CCK-8 assay (Figs. 6 and S4). First, the N/P ratios of RS-NCs were optimized for reducing cancer cell viability (Fig. 6A-C). In Fig. 6A, the CGI siRNA reduced 22%, 24%, and 24% of cancer cell viability when N/P ratios are 5. 7.5, and 10 with statistical significance (p -values: 1.1 x 10-8, 2.3 x 10-3, and 6.9 x 10-5). N/P ratio of 5 was chosen for the following experiments. In Fig. 6B, Kaiso siRNA reduced 15% of cancer cell viability when the N/P ratio was 10 with statistical significance (p -values: 1.5 x 10-3). On the other hand, in Fig. 6C, PICH siRNA inhibited 9% and 15% of cancer cell viability when the N/P ratio was 1 and 10 with statistical significance (p -values: 2.1 x 10-2 and 1.2 x 10-3).
Second, cell viability was measured under various CGI siRNA concentrations via RS-NC-mediated delivery (Fig. 6D). The 100, 200, and 400 nM CGI siRNAs via RS-NC reduced 17%, 22%, and 36% of cancer cell viability with statistical significance (p -values: 1.2 x 10-3, 6.5 x 10-6 and 3.2 x 10-6). Third, mRNA expression was quantified using quantitative polymerase chain reaction when Kaiso and PICH siRNAs were delivered to MDA-MB-231 cells via NCs (Fig. 6E). Resultantly, RS- and R11-NCs reduced 56% and 13% of Kaiso mRNA expression compared to the non-treated group. RS- and R11-NCs reduced 22% and 11% of PICH mRNA expression compared to the non-treated group. RS-NCs reduced statistically significant Kaiso and PICH mRNA expression compared to R11-NCs (p -value = 1.9 x 10-5 and 4.0 x 10-3).