Figure 1.
In vitro sensitivity to HER-2-redirected HSV and to trastuzumab.
(A) Cytotoxicity of R-LM249 for cells with high (SK-OV-3, MDA-MB-453 and BT-474) or very low/negative (MDA-MB-231) HER-2 expression. Cells were infected with R-LM249 (10 pfu/cell). Cell viability was measured at the indicated days after infection, by alamarBlue assay. Each point represents the average of quadruplicates + SD expressed as percentage with respect to uninfected cells. (B) Effect of trastuzumab after 72 hr culture. Mean and SEM from 3–5 independent experiments is shown.
Figure 2.
Therapy with the HER-2-redirected oncolytic HSV, R-LM249, of nude mice bearing i.p. human SK-OV-3 ovarian carcinoma.
Red arrows below x-axis mark the days in which groups of 5 mice received weekly i.p. treatments with R-LM249 (2×107 p.f.u./treatment) or vehicle (PBS). Significance of curve comparison: p = 0.02 by the Mantel-Haenszel test.
Figure 3.
Therapy with R-LM249 of Rag2−/−;Il2rg−/− mice bearing i.p. human SK-OV-3 ovarian carcinoma.
(A–C) incidence of peritoneal carcinomatosis, weight of metastatic lesions (mean + SEM) and incidence of ascites fluid in groups of 5–7 mice. Statistically significant differences: panel B, p = 0.007 at Student's t test; panel C, p = 0.027 at Fisher's exact test. (D) control mouse, treated with vehicle (PBS) alone, showing multiple i.p. masses (green arrows); (E) tumor-free mouse treated with R-LM249; (F) distribution of R-LM249 in a mouse bearing multiple i.p. tumors shows that the virus selectively populates and replicates in the HER-2+ masses (green fluorescence: virally-encoded EGFP; yellow-brown florescence: autofluorescence of mouse fur and visceral organs).
Figure 4.
Therapy with R-LM249 of Rag2−/−;Il2rg−/− mice bearing s.c. BT-474 or MDA-MB-453 human breast carcinoma cell lines.
(A) and (B), tumor volumes. R-LM249 was administered intratumorally at the indicated amounts (p.f.u.) on the days marked by red arrows below x-axis. Mean + SEM of 5 mice per group is shown, until all mice per group are alive. Statistical significance of treatment (at Student's t test): panel A, p<0.05 at least from day 13 (108 dose) or 20 (2×107 dose); panel B: p<0.05 at least from day 13 (both doses). (C) and (D), Kaplan-Meier analysis. End of therapy is shown by a vertical dashed line. Median survival times (days) for BT-474 groups were: Vehicle = 73, R-LM249 dose 2×107 = 139, dose 108 = 146. Median survival times (days) for MDA-MB-453 groups were: Vehicle = 98, R-LM249 dose 2×107 = 125, dose 108 = 132. Survival curves of treated groups were significantly different from the respective vehicle (p<0.01 at least, Mantel-Haenszel test).
Figure 5.
Therapy with R-LM249 of systemic metastases induced by the i.v. injection of human breast carcinoma cell line MDA-MB-453.
R-LM249 was administered i.p. at 108 pfu dose (4 weekly injections) to groups of 9–10 Rag2−/−;Il2rg−/− mice. (A, C, E) incidence of macroscopic metastases in the indicated organs, as determined at necropsy; (B, D, F) total metastatic burden (mean + SEM) in organs as quantified by human centromeric DNA qPCR. Statistical analysis of differences: panel A, p<0.0001 at Fisher's exact test; panel B, p = 0.0004 at both Student's t and non-parametric Wilcoxon rank sum tests; panel C, p = 0.07 at Fisher's exact test; panel D, p = 0.056 at Student's t test and p = 0.03 at non-parametric Wilcoxon rank sum test.
Figure 6.
Biodistribution of R-LM249 injected by the intraperitoneal route at 108 pfu in Rag2−/−;Il2rg−/− mice bearing MDA-MB-453 metastases.
Mean and SEM is shown for 2–3 mice. The number of copies of R-LM249 normalized over the quantity of total DNA extracted from the organ is reported. “pre” corresponds to organs of a mice that did not receive R-LM249.