Figure 5: M-MDSCs and TAMs targeted by folate delivered toll-like receptor 7 agonist and phosphoinositide 3-kinase inhibitor controls tumor growth and metastatic development.

(A and B) Inhibition of tumor growth by folate mediated delivery of TLR7a (FA-TLR7a) and PI3Ki (FA-PI3Ki) to MDSCs and TAMs. Balb/c mice (6–8 weeks old) were implanted with 0.05 million 4T1 tumor (Subcutaneous). On day 4 post tumor implantation, animals were treated with folate-conjugated TLR7 agonist (10 nmol/mouse), or non-targeted TLR7 agonist (10 nmol/mouse), or competition (200x free folate) with folate-conjugated TLR7 agonist (10 nmol/mouse) daily for 5 days per week. The tumor growth (A) and animal weight change (B) were monitored during the study. (C and D) Control of tumor growth by FRβ targeted reprogramming of MDSCs and TAMs by FA-PI3Ki. Balb/c mice (6–8 weeks old) were implanted with 0.05 million 4T1 tumor (subcutaneous). On day 4 post tumor implantation, animals were treated with folate-conjugated PI3K inhibitor (10 nmol/mouse), or non-targeted PI3K inhibitor (10 nmol/mouse), or competition (200x free folate) with Folate-conjugated PI3K inhibitor (10 nmol/mouse) daily for 5 days per week. The tumor growth (C) and animal weight change (D) were monitored during the study. (E and F) Impact of FA-TLR7a and FA-PI3Ki metastasis in 4T1 tumor bearing mice. 0.05 million 4T1 cells were implanted in the fat pad in 6–8-week-old balb/c mice (n=3). Treatment was started at day 6 post implantation and was continued for 14 days daily (IV). FA-TLR7 agonist, FA-PI3K inhibitor, TLR7 agonist, PI3K inhibitor (10 nmol/mouse) (defined in panels A and B). At the end of in vivo study, metastasis to the lung was evaluated in disease control and treatment groups by co-culture lung digested cells with 6-thioguanine (60 μM) for 14 days as described in methods (E and F). Data are compiled from two independent experiments with 4–5 mice per group.