Figure 1. Patient-derived tumor organoid (PDO) platforms that recapitulate the immune tumor microenvironment.

The immune tumor microenvironment can be constructed in PDOs via several approaches. (A) In the assembloid PDO platform, organoids containing exclusively tumor cells, often from physically and enzymatically dissociated tissues, are cultured in an extracellular matrix dome (Matrigel or BME) and submerged beneath tissue culture medium. In parallel, immune cells are isolated from peripheral sources (i.e., peripheral blood, lymph node) or from the tumor (i.e., tumor infiltrating lymphocytes, TIL) and subsequently co-cultured with the tumor organoid. (B) Alternatively, these isolated immune cells can be combined with physically and enzymatically dissociated tumors before submerging in an extracellular matrix dome. (C) Several PDO platforms have incorporated native tumor-infiltrating immune cells. In the patient- and murine-derived organotypic tumor spheroid (PDOTS/MDOTS) platform, tumors are physically and enzymatically dissociated, filtered to obtain appropriately sized spheroids, resuspended in a collagen matrix, then the spheroid-collagen mixture is injected into a 3D microfluidic culture device. (D) In the air-liquid interface (ALI) platform, physically dissociated tumor fragments are embedded in a collagen matrix on top of a transwell insert that is exposed to air with culture medium below it. (E) In the patient-derived tumor fragment (PDTF) platform, 1–2 mm³ tumor fragments are cut from different regions within a tumor and individually embedded into a collagen-based extracellular matrix with culture medium placed on top. Figure created with BioRender.com.