Hypoxia potentiates the inflammatory fibroblast phenotype promoted by pancreatic cancer cell-derived cytokines

Abstract

Cancer-associated fibroblasts (CAFs) are a major cell type in the stroma of solid tumors and can exert both tumor-promoting and tumor-restraining functions. This functional heterogeneity is correlated with the existence of transcriptionally distinct subpopulations of CAFs. CAF heterogeneity is observed in pancreatic ductal adenocarcinoma (PDAC), a tumor characterized by a remarkably dense and hypoxic stroma that features tumor-restraining myofibroblastic CAFs (myCAFs) and tumor-supporting inflammatory CAFs (iCAFs). While CAF heterogeneity can be driven in part by tumor cell-produced cytokines, other determinants shaping CAF identity and function are largely unknown. In vivo, we found that iCAFs display a hypoxic gene expression and biochemical profile and are enriched in hypoxic regions of PDAC tumors. Hypoxia leads fibroblasts to acquire an inflammatory gene expression signature and synergizes with cancer cell-derived cytokines to promote an iCAF phenotype in a HIF-1α dependent fashion. Furthermore, we show that HIF-1α stabilization is sufficient to induce an iCAF phenotype in stromal cells introduced into PDAC organoid co-cultures and to promote PDAC tumor growth. These findings indicate hypoxia-induced HIF-1α as a regulator of CAF heterogeneity and promoter of tumor progression in PDAC.

Exploring New Dimensions of Tumor Heterogeneity: The Application of Single Cell Analysis to Organoid‐Based 3D In Vitro Models

“…Hydrogels also offer a simple strategy for creating co-culture models that reflect microenvironmental heterogeneity, as multiple cell types can be cultured in a single gel dome. This approach has been used to create tumor-fibroblast, [65,[80][81][82][83] tumorlymphocyte, [83][84][85] tumor-myeloid, [86][87][88] and tumor-fibroblastimmune [78,83,84] co-cultures. These co-culture models have been used to show how tumor cells influence stromal cell phenotypes and vice versa, investigate the mechanisms underpinning these effects, and explore strategies for enhancing therapeutic response, among other applications.…”

“…These co-culture models have been used to show how tumor cells influence stromal cell phenotypes and vice versa, investigate the mechanisms underpinning these effects, and explore strategies for enhancing therapeutic response, among other applications. [65,80,83,86] Furthermore, hydrogel-based co-culture models can accommodate the addition of normal tissue organoids, which may be valuable for some applications, such as assessing off-target effects of tumor-targeted treatments. For example, colorectal carcinoma (CRC) PDOs were combined with CAR NK cells and normal colon organoids to assess the efficacy of a novel CAR NK target and evaluate the offtarget toxicity of CAR NK cells.…”

“…[89,90] Furthermore, a mixed co-culture model of murine PSCs and PDAC organoids in hypoxia showed that PSC activation to CAFs is HIF-dependent. [80] As the levels of oxygen tension in hypoxia chambers are more static than the cell-consumption derived gradients present in the TME, newer hydrogels with dynamic systems that better recapitulate gradients present in the TME of stiffness, signaling molecules, oxygen and other features may be of interest for future incorporation of PDOs. [91][92][93][94][95][96][97] The versatility and customizability of hydrogels allows them to be used as the basis for more complex 3D in vitro models including layered hydrogel systems and micropatterned/micromolded gels (Figure 2Ci).…”

Hypoxia at 3D organoid establishment selects essential subclones within heterogenous pancreatic cancer

“…Hypoxia is a key microenvironment associated with malignant traits (Schito and Semenza, 2016;Shah et al, 2020;Tao et al, 2021), including epithelial-mesenchymal transition (EMT) and chemotherapy resistance (Chang et al, 2011;Chen et al, 2016;Geyer et al, 2023). Pancreatic ductal adenocarcinoma (PDAC) is known to be extremely hypoxic due to hypovascularity and abundant stroma composed of fibroblasts and inflammatory cells (Jing et al, 2019;Schwörer et al, 2023). This severe hypoxia accelerates malignancy while typical cellular heterogeneity within tumors increases hypoxia adaptation (Mujcic et al, 2013;Rouschop et al, 2013).…”