Abstract 3942: Differential expression of a novel transport receptor, SORT1 (sortilin), in cancer versus healthy tissues that can be utilized for targeted delivery of anti-cancer drugs
Authors: Roy Guylaine , Kadekar Pratik , Douglas Lynn Marie , Frappier Maude , Currie Jean-Christophe , Dhillon Jess , Cesarone Gregory , Siderits Richard , Kirchner Karen , Demeule Michel , Marsolais Christian 
Published: April 2023

Sortilin (SORT1), or neurotensin receptor-3, is a scavenging receptor in the Vacuolar Protein Sorting 10 protein (Vps10p) family. SORT1 is involved in the internalization and trafficking of its ligands through an endocytic process and is associated with cancer cell survival and progression, making SORT1 a candidate for novel drug delivery. We recently reported on the pattern and prevalence of SORT1 expression in endometrial, breast, ovarian, colorectal, pancreas cancers, and skin melanoma. To better understand SORT1 expression, we screened tissues from different cancer types using the same immunohistochemistry (IHC) method. A total of 19 cancer tissue microarrays (TMAs) with 1394 evaluable cancer cores were screened. Each cancer core was scored using an H-score ranging from 0 to 300, where 0 corresponds to no cell stained for SORT1, while 300 corresponds to strong SORT1 staining in all cells. The table below summarizes the % of cores with moderate to high SORT1 expression (defined as H-score ≥100) as well as the average H-Score for each cancer type evaluated. Sub-analyses of SORT1 expression by tumor histological sub-type, stage and grade are also being performed.

A total of 234 healthy or normal adjacent tissues cores were also assessed. Weak or null staining was observed in these tissues. Moderate staining was observed in specific cell types in kidney tubules and glomeruli, colonic mucosa, splenic sinusoidal spaces in red pulp, blood vessels in smooth muscle of spleen and colon, dendritic and axonal extensions of pyramidal-type neurons in brain, and testicular seminiferous tubules. SORT1 is currently being studied as a cancer target in a first-in-human (FIH) study of a peptide-drug conjugate (clinicaltrial.gov: NCT04706962). These results suggest that SORT1 is highly expressed in multiple tumors and is a promising target for the delivery and internalization of cancer therapeutic agents.

Table 1. Cancer Type No. evaluable cores % of indication with H-score ≥ 100 Average H-Score Endometrial 94 90 197 Thyroid 108 92 188 Melanoma 155 83 184 Lung 152 58 112 SCLC 44 95 183 NSCLC 108 43 82 Bladder 118 81 156 Testis 40 100 116 Small intestine 54 63 102 Eye 26 46 83 Cervix 376 38 75 Prostate 150 39 71 Liver 121 23 52

Citation Format: Guylaine Roy, Pratik Kadekar, Lynn Marie Douglas, Maude Frappier, Jean-Christophe Currie, Jess Dhillon, Gregory Cesarone, Richard Siderits, Karen Kirchner, Michel Demeule, Christian Marsolais. Differential expression of a novel transport receptor, SORT1 (sortilin), in cancer versus healthy tissues that can be utilized for targeted delivery of anti-cancer drugs. [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 3942.