LAUSR

Background: In colorectal cancer (CRC), versican (VCAN) accumulation has been found to negatively correlate with CD8+ tumor infiltrating lymphocyte (TIL) abundance and its proteolysis into versikine (Vkine) positively correlates with TIL abundance. TIMP3 has demonstrated the ability to inhibit several ADAMTS proteases able to cleave VCAN to Vkine. Here we investigate the correlation of TIMP3 accumulation in CRCs with the VCAN status and CD8+ T cell infiltration. Methods: Matched primary and metastatic CRC samples from 156 patients who had resected oligometastatic CRC were stained for VCAN, Vkine, TIMP3, and CD8+ TILs. VCAN, Vkine, and TIMP3 were scored using an intensity binning system ranging from 0-3+ and T cells in the epithelium were reported per high power field (HPF). Tumors were designated as high (2 or 3+) or low (0 or 1) for both VCAN and Vkine and positive (+; 1-3) or negative (0) for TIMP3. Tumors designated VCAN low and Vkine high are considered VCAN proteolytic predominant (VPP) and all other combinations are considered VCAN proteolytic weak (VPW). Results: Across the whole dataset, 52% of cancers were VCAN high and 24% were VPP. TIMP3 was detected in 33% of cancers. The frequency of TIMP3 was similar between primary and metastatic tumors (39% and 29%, respectively). Of the VCAN high cancers, 42% were TIMP3+ whereas 61% of the TIMP3+ samples are VCAN high. Of the Vkine high cancers, 44% were TIMP3+ and 36% of VPP cancers were TIMP3+. The prevalence of the VPP phenotype was similar between the TIMP3+ and negative cancers. Additionally, among the TIMP3+ samples 68% were Vkine high versus 46% in TIMP3 negative cancers (p=0.001). VCAN proteolysis correlates with higher CD8+ TIL abundance, thus we assessed the number of CD8+ TILs in TIMP3+ and negative tumors. The TIMP3+ cancers had a median of 2 CD8+ TILs/HPF and the TIMP3 negative cancers has a median of 3 CD8+ TILs/HPF. For VPP cancers, those that were also TIMP3+ had a median of 3 CD8+ TILs/HPF compared to TIMP3 negative cancers which had a median of 6 CD8+ TILs/HPF (p=0.2). Conclusions: TIMP3 correlates with higher levels of VCAN accumulation but does not correlate with lower levels of proteolysis. Future studies are needed to better clarify the impact of TIMP3 and other mediators in regulating VCAN accumulation and proteolysis in the tumor microenvironment. Citation Format: Anna Field, Sean Kraus, Kristina Matkowskyj, Dustin Deming, Cheri A. Pasch, Wei Zhang. Potential of TIMP3 regulating the versican status in the colorectal cancer tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4647.