(476b) Molecular Engineering of Aminoglycoside-Derived Hydrogel Platform for 3D Organoid Generation As a Cancer Dormancy Model

Engineering three dimensional (3D) tissue models can significantly transform the treatment of diseases such as cancer since these models are better physiological representations in terms of cell type heterogeneity, cell-cell, cell-extracellular matrix and cell-biomolecule interactions. These 3D tissue models can thus better predict the clinical response for chemotherapeutic drugs compared to 2D monolayer cultures, which are still predominantly used for cell-based assays. Successful implementation of chemotherapeutic regimens that can target both proliferative and dormant cancer cells is limited due to the lack of suitable experimental models for tumor cell dormancy. Cancer cell dormancy is characterized by growth arrest in the G0/G1 phase of the cell cycle and the resistance to traditional therapies that target actively proliferating cells. Current chemotherapeutic regimens suffer from drug resistance; these therapeutics target the actively proliferating cells but not the dormant cancer cells. These resistant and dormant cells can reactivate once the microenvironment becomes favorable, causing tumor relapse at the primary site or at a distant metastatic site. Clearly, there is an urgent need to engineer in vitro models of tumor dormancy to facilitate fundamental understanding and enable high-throughput screening of different chemotherapeutic drugs and their combinations. In this research, we describe a novel aminoglycoside-derived hydrogel (Amikagel) platform which can facilitate the generation of dormant three-dimensional tumor microenvironments (3DTMs) using different types of cancer cells such as bladder cancer (T24), breast cancer (T47D), and melanoma (A375) cell lines. Amikagels are formed by crosslinking the monomers aminoglycoside amikacin hydrate with polyethylene glycol diglycidyl ether (PEGDE). The chemo-mechanical properties of these amikagels, including gel stiffness and cell adhesivity, can be tuned by varying the molar ratios of amikacin hydrate (amine) to PEGDE to generate dormant 3DTMs of different cancer cell lines. Cells in these dormant 3DTMs were arrested in G0/G1 phase of the cell cycle, contributing resistance to most of the conventional drugs which demonstrate activity in proliferating cells. Preliminary results showed a significant upregulation of ribosomal protein genes (protein translation), cell cycle arrest, cell-cell adhesion genes, transmembrane proteins, tumor suppressors, anti-proliferation and cytoskeletal kinases, and protein transport genes in 3DTMs compared to actively dividing controls. 3DTMs were also characterized by hypoxia and differential modulation of stemness markers compared to 2D monolayer cultures. Novel treatments, including those targeting the endoplasmic reticulum stress pathway, caused significant ablation of these dormant 3DTMs. Amikagels have also been used to generate heterogeneous islet organoids from human embryonic stem cell derived pancreatic progenitor cells (hESC-PP). Future work involves generation of encapsulated 3DTMs for implantation to establish in vivo dormancy models. Different encapsulation strategies for 3DTMs using polymer coatings are currently being evaluated to facilitate their implantation in vivo. In conclusion, this chemically-diverse amikagel technology can be used for generating 3DTMs to better understand the biochemical factors influencing dormancy, high-throughput drug screening, as well as engineering complex human-specific organoids from human pluripotent stem cells (hPSCs) for regenarative medicine applications.