Modified Salmonella Typhimurium with IL-18 gene as treatment option for aggressive and metastatic colorectal cancer: Assessing the therapeutic potential in a metastatic CRC organoid mouse model and human colorectal cancer organoids

• Grant number: 24/01808-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): September 01, 2024
• Effective date (End): August 31, 2025
• Field of knowledge: Biological Sciences - Immunology - Applied Immunology
• Principal Investigator: Fernanda de Freitas Anibal
• Grantee: Talita Motta Quiarim
• Supervisor: Rebecca Kesselring
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Research place: Universitätsklinikum Freiburg, Germany
• Associated to the scholarship: 22/06194-0 - Assessment of IL-18 gene expression using Salmonella typhimurium in the control of colorectal cancer cells in vitro and in vivo., BP.DR

Abstract

Colorectal cancer (CRC) is the third most common cancer in the world, and it is considered a global health issue. It is a multifactorial disease that involves genetic, environmental and lifestyle risk factors. CRC has one of the highest mutational burdens of all cancer types, and APC, TP53 and KRAS are the most recurrent mutated genes in metastasis. Even though there is a significant progress in cancer therapy, most of the patients struggles with the disease due to resistance to chemotherapies, and dies within 5 years after initial diagnosis, highlighting the urgent need to find new therapeutic approaches in CRC treatment, in special metastatic CRC. It is known that the microbiome has an important role in the development of CRC and new research shows the importance of the usage of bacteria as a potent antitumour agent and they can be genetically manipulated to carry antitumour agents to be released in the tumour microenvironment. Salmonella Typhimurium has been extensively studied as a promising bacteria used in the delivery of anti-cancer agents, since it can survive in both aerobic and anaerobic environments and has a preference to colonize tumour microenvironment, housing small to large tumours, even metastasis sites accessing via circulatory system, and they are able to stimulate innate and acquire immune responses against tumour cells. Interleukin-18 (IL-18) is a pro-inflammatory and immunoregulatory cytokine member of the IL-1 family of cytokines and has been found as a key regulator to mucosal homeostasis in the gastrointestinal (GI) tract and numerous studies proposed that IL-18 can be a useful therapeutic agent for CRC. In this project, a metastatic CRC mouse model with orthotopic transplantation of APTAK organoids will be used to realistically mimic the carcinogenesis and metastasis of UICC stage IV CRC patients. APTAK organoids are aggressive tumour organoids from mouse intestinal epithelial cells that are engineered to be devoid of APC, TP53, Tgfbr2 and express constitutively active KRAS (KrasG12D) and an activated/myristoilated isoform of Akt1. This organoid mimic a primary colonic tumour with a high metastatic potential, containing invasive features that give rise to metastasis in up to 80% of inoculated mice, mostly in the liver and peritoneum and occasionally the lung. Moreover, the previously constructed Salmonella Typhimurium (SL3261) modified with IL-18 gene will be used in the treatment of APTAK organoids in vitro and in vivo, both in primary CRC and metastasis. In addition, the role of the modified bacteria will be analysed in the gut microbiome of mice inoculated with APTAK organoids. Human organoids from primary CRC and CRC metastasis will be available for in vitro assays to evaluate the role of IL-18 in the treatment of CRC human organoids and if suitable in PDTO (patient-derived tumour organoid) CRC mouse models.