The work outlined herein describes AU-011, a novel recombinant papillomavirus-like particle (VLP) drug conjugate and its initial evaluation as a potential treatment for primary uveal melanoma. The VLP is conjugated with a phthalocyanine photosensitizer, IRDye 700DX, that exerts its cytotoxic effect through photoactivation with a near-infrared laser. We assessed the anticancer properties of AU-011 utilizing a panel of human cancer cell lines and using murine subcutaneous and rabbit orthotopic xenograft models of uveal melanoma. The specificity of VLP binding (tumor targeting), mediated through cell surface heparan sulfate proteoglycans (HSPG), was assessed using HSPG-deficient cells and by inclusion of heparin in studies. Our results provide evidence of potent and selective anticancer activity, both and AU-011 activity was blocked by inhibiting its association with HSPG using heparin and using cells lacking surface HSPG, indicating that the tumor tropism of the VLP was not affected by dye conjugation and cell association is critical for AU-011-mediated cytotoxicity. Using the uveal melanoma xenograft models, we observed tumor uptake following intravenous (murine) and intravitreal (rabbit) administration and, after photoactivation, potent dose-dependent tumor responses. Furthermore, in the rabbit orthotopic model, which closely models uveal melanoma as it presents in the clinic, tumor treatment spared the retina and adjacent ocular structures. Our results support further clinical development of this novel therapeutic modality that might transform visual outcomes and provide a targeted therapy for the early-stage treatment of patients with this rare and life-threatening disease. .

<p>Figure S1-video composites of real time AU-011 mediated killing of 92.1MEL cells; Figure S2-Killing and binding comparison of free IR700 dye to VLP conjugated IR700 (AU-011) on HeLa and 92.1MEL cells; Figure S3-Demonstration of both the AU-011 dose and light fluence required for AU-011 killing activity on HeLa and 92.1 cells; Figure S4-Examples of the AU-011 EC50 binding and killing curves using 8 tumor cell lines and contributing to values supplied in Table 1; Figure S5-Example of the flow cytometry gating strategy used to obtain the values plotted in the mixed cell experiment shown in Figure 2; Figure S6-Companion confocal images showing time course uptake of AU-011 in 92.1MEL tumors implanted in the eyes of rabbits and quantified in Figure 4; Figure S7-H&E staining of 92.1MEL tumors implanted in rabbit eyes showing dose response effect of AU-011 8-9 days post-treatment.</p>

<p>Figure S1-video composites of real time AU-011 mediated killing of 92.1MEL cells; Figure S2-Killing and binding comparison of free IR700 dye to VLP conjugated IR700 (AU-011) on HeLa and 92.1MEL cells; Figure S3-Demonstration of both the AU-011 dose and light fluence required for AU-011 killing activity on HeLa and 92.1 cells; Figure S4-Examples of the AU-011 EC50 binding and killing curves using 8 tumor cell lines and contributing to values supplied in Table 1; Figure S5-Example of the flow cytometry gating strategy used to obtain the values plotted in the mixed cell experiment shown in Figure 2; Figure S6-Companion confocal images showing time course uptake of AU-011 in 92.1MEL tumors implanted in the eyes of rabbits and quantified in Figure 4; Figure S7-H&E staining of 92.1MEL tumors implanted in rabbit eyes showing dose response effect of AU-011 8-9 days post-treatment.</p>

<div>Abstract<p>The work outlined herein describes AU-011, a novel recombinant papillomavirus-like particle (VLP) drug conjugate and its initial evaluation as a potential treatment for primary uveal melanoma. The VLP is conjugated with a phthalocyanine photosensitizer, IRDye 700DX, that exerts its cytotoxic effect through photoactivation with a near-infrared laser. We assessed the anticancer properties of AU-011 <i>in vitro</i> utilizing a panel of human cancer cell lines and <i>in vivo</i> using murine subcutaneous and rabbit orthotopic xenograft models of uveal melanoma. The specificity of VLP binding (tumor targeting), mediated through cell surface heparan sulfate proteoglycans (HSPG), was assessed using HSPG-deficient cells and by inclusion of heparin in <i>in vitro</i> studies. Our results provide evidence of potent and selective anticancer activity, both <i>in vitro</i> and <i>in vivo</i>. AU-011 activity was blocked by inhibiting its association with HSPG using heparin and using cells lacking surface HSPG, indicating that the tumor tropism of the VLP was not affected by dye conjugation and cell association is critical for AU-011–mediated cytotoxicity. Using the uveal melanoma xenograft models, we observed tumor uptake following intravenous (murine) and intravitreal (rabbit) administration and, after photoactivation, potent dose-dependent tumor responses. Furthermore, in the rabbit orthotopic model, which closely models uveal melanoma as it presents in the clinic, tumor treatment spared the retina and adjacent ocular structures. Our results support further clinical development of this novel therapeutic modality that might transform visual outcomes and provide a targeted therapy for the early-stage treatment of patients with this rare and life-threatening disease. <i>Mol Cancer Ther; 17(2); 565–74. ©2017 AACR</i>.</p></div>