Human cancer evolution in the context of a human immune system in mice

Area of Science:

• Oncology
• Immunology
• Preclinical Models

Background:

• Immunotherapy shows promise for cancer treatment, but effective preclinical in vivo models are lacking.
• Humanized immune system (HIS) mice, generated using CD34+ hematopoietic stem cells, are being explored as a potential model.
• Understanding tumor microenvironments (TMEs) is crucial for developing effective cancer therapies.

Purpose of the Study:

• To evaluate the ability of transplanted human cancer cells to form primary tumors and metastasize in HIS mice.
• To investigate the tumor microenvironment and immune cell infiltration within these models.
• To assess the utility of HIS mice as a preclinical model for immunotherapeutic strategies.

Main Methods:

• Transplantation of human cancer cells into HIS mice.
• Monitoring of primary tumor growth and spontaneous metastasis (lung, liver).
• Analysis of tumor-infiltrating lymphocytes (CD8+ T cells, regulatory T cells) and programmed death ligand 1 (PDL1) expression.

Main Results:

• All transplanted cancer cell lines formed primary tumors that progressed synchronously.
• Spontaneous lung and liver metastases were observed from both orthotopic and ectopic tumors.
• Tumor spread inversely correlated with CD8+ T cell infiltration; some models showed immune exclusion or adaptive resistance (PDL1, Treg recruitment).
• Tumor microenvironments in HIS mice models resembled those in clinical cancers.

Conclusions:

• HIS mice provide a valuable in vivo preclinical model for studying human cancer and evaluating immune modulatory therapies.
• Different HIS mouse models recapitulate distinct human TMEs, enabling research into disease-specific mechanisms and therapeutic responses.