EP1075 - Targeting the Complement System in the Treatment of Colorectal Cancer

ePoster Presenter(s)

• 

  Emily Vu Nghiem, MD (she/her/hers)

  Postdoctoral Research Fellow / Surgical Resident
  Albert Einstein College of Medicine / Montefiore Medical Center
  Albert Einstein College of Medicine
  Bronx, NY, United States

  Disclosure information not submitted.

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Senior Author(s)

• CK

  Chaoyuan Kuang, M.D., Ph.D.

  Assistant Professor of Oncology and Medicine
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

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Author(s)

• YS

  Yvonne Saenger, M.D.

  Associate Professor, Hematology & Oncology, Microbiology & Immunology, and Pathology
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

  Disclosure information not submitted.
• LL

  Lawrence Leung, Ph.D.

  Research Assistant Professor
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

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• GE

  Gerardo Espinoza, n/a

  Research Technician
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

  Disclosure information not submitted.
• MM

  Mahshid Mohammadi, Ph.D.

  Postdoctoral Fellow
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

  Disclosure information not submitted.
• DK

  Divya Kenchappa, Ph.D.

  Postdoctoral Fellow
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

  Disclosure information not submitted.
• AS

  Ajay Singh, Ph.D.

  Postdoctoral Fellow
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

  Disclosure information not submitted.
• TL

  Terence Li, n/a

  Research Technician
  Albert Einstein College of Medicine / Montefiore Medical Center
  Bronx, New York, United States

  Disclosure information not submitted.

Purpose/Background: Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Up to 30% of patients present at stage 4 while up to half of patients who undergo curative intent treatments progress to metastatic disease, conferring a 5-year survival rate of only 15%. Firstline treatment of metastatic CRC (mCRC) involves a combination of chemotherapy and targeted therapy, however the disease eventually becomes refractory. The advent of PD1/PD-L1 immune checkpoint inhibitors have shown proof of principle for targeting the immune system in CRC but are only efficacious for a small cohort of patients, underlining the need for novel treatment options. The complement system is an evolutionarily ancient part of the immune system ubiquitous to tumors in all patients. C3 is a central protein in the cascade, where all three activation pathways converge. Its cleavage produces anaphylatoxin C3a which has been shown to play a role in epithelial-mesenchymal transition (EMT) via suppression of E-cadherin, therefore promoting tumor metastasis and making it a promising target in cancer therapy. C3a has also been found at significantly higher levels in serum from CRC patients as compared to healthy individuals.

Methods/Interventions: Using human CRC cell lines and a normal colon epithelial cell line, as well as a patient-derived organoid (PDO) model of CRC, we studied the therapeutic potential of C3aR inhibitor SB290157 trifluoroacetate. In vitro viability was measured by chemical cell proliferation assays and cell migration was assessed using a scratch assay. Spatial proteomics was performed on patient tumor tissues using the NanoString GeoMx platform with multiplex immunofluorescence (IF) staining to assess protein expression and localization within the tumor microenvironment.

Results/Outcomes: Quantitative IF staining of patient tumor tissue demonstrated positive C3 expression at a density of 15 cells/mm2. Treatment of cell lines and a PDO with C3aR inhibitor demonstrated decreased cell and organoid viability in a dose-dependent fashion. The drug IC50 was lower for the treatment of CRC cell lines as compared to treatment of a normal colon epithelial cell line. Scratch assay demonstrated that treatment with C3aR inhibitor similarly decreased cell migration in a dose-dependent fashion.

Conclusion/Discussion: Using spatial proteomics, we found that patient tumor tissues were positive for C3 expression, indicating a potential role in the tumorigenesis of CRC. Our results demonstrated that the C3aR inhibitor SB290157 trifluoroacetate was efficacious in suppressing the growth of human CRC cell lines and a PDO model of CRC, as well as in decreasing cell migration. We also found that C3aR inhibition more potently suppressed growth in CRC cell lines as compared to a normal colon epithelial cell line, further indicating its potential tumorigenic role. The complement system remains a largely unexplored frontier in cancer therapy, and our promising results with C3aR inhibition warrant further investigation of complement as a target in the treatment of CRC.

Figure 1
Figure 1A: Quantitative immunofluorescence staining of patient tumor tissue demonstrating staining of C3, CD68, and PAN-CK with table of corresponding cell density.

Figure 1B: Graph of cell viability of various CRC cell lines after 2-day treatment with C3aR inhibitor at indicated drug concentrations. Dotted line represents IC50.

Figure 1C: Graph of cell migration at hours 0-48 of RKO scratch assay after treatment with C3aR inhibitor at indicated drug concentrations.

Figure 1D: Images of RKO scratch assay after treatment with C3aR inhibitor at indicated drug concentrations at 0, 24, and 48 hours.

Figure 1E: Graph of cell viability of PDO CRC 22-008 after 4-day treatment with C3aR inhibitor at indicated drug concentrations.

Figure 1F: Images of PDO CRC 22-008 on day 4 of treatment with C3aR inhibitor at indicated drug concentrations.