(i) Supplementary Methods 1. Synthesis of L-BPD and L-IRI via freeze-thaw extrusion method 2. Pharmacokinetics and biodistribution of L-BPD and L-IRI 3. In-vitro quantification of changes in ABCG2 expression using immunofluorescence 4. Ultrasound Imaging 5. Histology and immunofluorescence of tumor samples 6. Quantification of H&E and immunofluorescence biomarkers 7. Determination of Synergism (ii) Supplementary Tables Supplementary Table S1. Comparison of PDT and irinotecan doses used in this study versus in clinic Supplementary Table S2. List of antibodies used for immunofluorescence Supplementary Table S3. The synergistic effect of combination PDT and L-IRI Supplementary Table S4. Physical parameters of L-BPD and L-IRI (iii) Supplementary Figures and Legends Supplementary Fig. S1. Treatment schedule and longitudinal monitoring of PanCa tumors in vivo Supplementary Fig. S2. Sub-cytotoxic PDT leads to decreased levels of ABCG2 and increased intracellular irinotecan in AsPC-1 cells Supplementary Fig. S3. Tumor growth kinetics of MIA PACa-2 and AsPC-1 in vivo Supplementary Fig. S4. Change in mouse body weight after combination treatment
ARTICLE ABSTRACT
The ability of tumor cells to adapt to therapeutic regimens by activating alternative survival and growth pathways remains a major challenge in cancer therapy. Therefore, the most effective treatments will involve interactive strategies that target multiple nonoverlapping pathways while eliciting synergistic outcomes and minimizing systemic toxicities. Nanoliposomal irinotecan is approved by the FDA for gemcitabine-refractory metastatic pancreatic cancer. However, the full potential of irinotecan treatment is hindered by several cancer cell survival mechanisms, including ATP-binding cassette G2 (ABCG2) transporter-mediated irinotecan efflux from cells. Here, we demonstrate that benzoporphyrin derivative-based photodynamic therapy (PDT), a photochemical cytotoxic modality that activates the apoptotic pathway, reduced ABCG2 expression to increase intracellular irinotecan levels in pancreatic cancer. Moreover, we show that PDT inhibited survivin expression. Although PDT potentiated irinotecan treatment, we also demonstrate that irinotecan reduced the tumoral expression of monocarboxylate transporter 4, which was upregulated by PDT. Notably, using orthotopic xenograft models, we demonstrate that combination of single low-dose PDT and a subclinical dose of nanoliposomal irinotecan synergistically inhibited tumor growth by 70% for 3 weeks compared with 25% reduction after either monotherapies. Our findings offer new opportunities for the clinical translation of PDT and irinotecan combination therapy for effective pancreatic cancer treatment. Cancer Res; 76(5); 1066–77. ©2015 AACR.
