Abstract 4025: Combination strategy of endoscopic resection and telomerase-targeting oncolytic virus for eradicating lymph node metastasis of submucosal invasive colorectal cancer

Abstract

Abstract Endoscopic resection is now one of the options as minimally invasive therapy for early colorectal cancer, However, surgical resection has been still standard for submucosal invasive colorectal cancer, because about 10% of that have LN metastasis. To secure endoscopic resection for submucosal invasive colorectal cancer, an alternative, innovational strategy to purge potential LN metastasis is required. We previously reported that a telomerase-dependent oncolytic adenovirus (OBP-301) spreads to the regional LNs, selectively replicates, and eradicates metastatic cancer cells in LNs, when administered into the orthotopically xenotransplanted rectal tumor in mouse model. In this study we evaluated whether OBP-301 could inhibit LN metastasis after the local resection mimicking endoscopic resection in a submucosal invasive rectal tumor mouse model. Human colon cancer HCT-116 cells expressing green fluorescent protein (GFP) were orthotopically implanted into the submucosal layer of the rectum in nude mouse, to develop resultant rectal tumor mimicking submucosal invasive one. LN metastasis was observed in 78.5% of mice as early as 7 days after cancer cell inoculation. The rectal tumor was injected with OBP-301 peritumorally, and then got locally excised mimicking Endoscopic submucosal dissection (ESD) technique. Seven days after tumor resection, the treatment with OBP-301 showed a significant inhibition in LN metastasis, whereas the other control treatment did not. Moreover, LN metastatic recurrence was not detected in OBP-301-treated group even 4 weeks after tumor resection. Similar results were also observed in another model with human colon cancer Colo-205-GFP cells. These results suggest that a novel combination of ESD and OBP-301 might have potential to take place of the conventional surgical approach in treating submucosal invasive colorectal cancer. Citation Format: Naoto Hori, Satoru Kikuchi, Hiroyuki Kishimoto, Hiroshi Tazawa, Yuuri Hashimoto, Shinji Kuroda, Shunsuke Kagawa, Yasuo Urata, Robert M. Hoffman, Toshiyoshi Fujiwara. Combination strategy of endoscopic resection and telomerase-targeting oncolytic virus for eradicating lymph node metastasis of submucosal invasive colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4025. doi:10.1158/1538-7445.AM2014-4025