Hypoxia-inducing cryogels uncover key cancer-immune cell interactions in an oxygen-deficient tumor microenvironment

Abstract

Hypoxia, an important feature of solid tumors, is a major factor shaping the immune landscape, and several cancer models have been developed to emulate hypoxic tumors. However, to date, they still have several limitations, such as the lack of reproducibility, inadequate biophysical cues, limited immune cell infiltration, and poor oxygen (O2) control, leading to non-pathophysiological tumor responses. As a result, it is essential to develop new and improved cancer models that mimic key features of the tumor extracellular matrix and recreate tumor-associated hypoxia while allowing cell infiltration and cancer-immune cell interactions. Herein, hypoxia-inducing cryogels (HICs) have been engineered using hyaluronic acid (HA) as macroporous scaffolds to fabricate three-dimensional microtissues and model a hypoxic tumor microenvironment. Specifically, tumor cell-laden HICs have been designed to deplete O2 locally and induce long-standing hypoxia. This state of low oxygen tension, leading to HIF-1α stabilization in tumor cells, resulted in changes in hypoxia-responsive gene expression and phenotype, a metabolic adaptation to anaerobic glycolysis, and chemotherapy resistance. Additionally, HIC-supported tumor models induced dendritic cell (DC) inhibition, revealing a phenotypic change in plasmacytoid B220+ DC (pDC) subset and an impaired conventional B220- DC (cDC) response in hypoxia. Lastly, our HIC-based melanoma model induced CD8+ T cell inhibition, a condition associated with the downregulation of pro-inflammatory cytokine secretion, increased expression of immunomodulatory factors, and decreased degranulation and cytotoxic capacity of T cells. Overall, these data suggest that HICs can be used as a tool to model solid-like tumor microenvironments and identify a phenotypic transition from cDC to pDC in hypoxia and the key contribution of HA in retaining cDC phenotype and inducing their hypoxia-mediated immunosuppression. This technology has great potential to deepen our understanding of the complex relationships between cancer and immune cells in low O2 conditions and may pave the way for developing more effective therapies.

Hypoxia‐activated ADCC‐enhanced humanized anti‐CD147 antibody for liver cancer imaging and targeted therapy with improved selectivity

“…Such hypoxia‐impaired immunological effects are in line with previous observations that other Abs decrease the ADCC, ADCP, and CDC in tumors 50–54 . The underlying mechanisms are unclear, but may be associated with hypoxia‐related downregulation of immune function 51,55,56 . The decreased but not disappeared ADCC induced by HAP18 Ab is attributed to enhanced ADCC characteristic of HcHAb18 Ab (Figure 2).…”

HIF-stabilizing biomaterials: from hypoxia-mimicking to hypoxia-inducing

“…In our latest work, our team engineered hypoxia-inducing cryogels (HICs) to create 3D microtissues with features of the hypoxic tumor microenvironment (TME). 43 Cryogels were fabricated at subzero temperature with chemically modified hyaluronic acid (HAGM), an essential component of the tumor-associated ECM, and RGD, a short peptide found in various proteins of the ECM. In addition, the scaffolds were grafted with immobilized GOX and CAT to deplete O 2 rapidly and safely ( Fig.…”

“…4 ). Strikingly, they maintained hypoxia for at least 6 days while remaining cytocompatible and biocompatible, 43 which is a significant improvement compared to HIHs. HICs also induced sustained cellular hypoxia and facilitated the reorganization of cancer cells (4T1 mammary carcinoma and B16-F10 melanoma) into microsized tumor masses.…”

Biomaterial-assisted local oxygenation safeguards the prostimulatory phenotype and functions of human dendritic cells in hypoxia

“…Mature DCs migrate to draining lymph nodes to initiate T-cell priming, triggering their activation and proliferation, thus inducing an adaptive immune response. However, low O 2 levels impede Tcell proliferation and function, ultimately suppressing the activities of helper T cells and cytotoxic T cells (2,48). Therefore, we explored the potential of O 2 -cryogels to preserve the allogeneic T-cell activation and proliferation, which is crucial for generating a robust adaptive immune response.…”