Stratified 3D Microtumors as Organotypic Testing Platforms for Screening Pancreatic Cancer Therapies

Abstract

Cancer‐associated pancreatic stellate cells installed in periacinar/periductal regions are master players in generating the characteristic biophysical shield found in pancreatic ductal adenocarcinoma (PDAC). Recreating this unique PDAC stromal architecture and its desmoplastic microenvironment in vitro is key to discover innovative treatments. However, this still remains highly challenging to realize. Herein, organotypic 3D microtumors that recapitulate PDAC‐stroma spatial bioarchitecture, as well as its biomolecular, metabolic, and desmoplastic signatures, are bioengineered. Such newly engineered platforms, termed stratified microenvironment spheroid models – STAMS – mimic the spatial stratification of cancer‐stromal cells, exhibit a reproducible morphology and sub‐millimeter size. In culture, 3D STAMS secrete the key molecular biomarkers found in human pancreatic cancer, namely TGF‐β, FGF‐2, IL‐1β, and MMP‐9, among others. This is accompanied by an extensive desmoplastic reaction where collagen and glycosaminoglycans (GAGs) de novo deposition is observed. These stratified models also recapitulate the resistance to various chemotherapeutics when compared to standard cancer–stroma random 3D models. Therapeutics resistance is further evidenced upon STAMS inclusion in a tumor extracellular matrix (ECM)‐mimetic hydrogel matrix, reinforcing the importance of mimicking PDAC‐stroma bioarchitectural features in vitro. The 3D STAMS technology represents a next generation of biomimetic testing platforms with improved potential for advancing high‐throughput screening and preclinical validation of innovative pancreatic cancer therapies.

Programmable Living Units for Emulating Pancreatic Tumor‐Stroma Interplay

“…For generating heterotypic 3D STAMS, a two‐step strategy was established as previously described. [ 5 ] In the first stage of assembly, a 3D spheroid core comprising PANC‐1 cells was placed in in vitro culture. At day 6 of maturation, a suspension of human pancreatic stellate CAFs was seeded in the wells containing a tumor core spheroid to establish the stratified 3D heterotypic model (devoid of ECM components).…”

“…[3,4] Recent endeavors have actively sought to better recapitulate human tumors via bioengineering of evermore advanced 3D in DOI: 10.1002/adhm.202102574 vitro models, including: i) 3D spheroids, ii) organoids, iii) extracellular matrix (ECM)mimetic hydrogel-based platforms, iv) porous based scaffolds, or v) microfluidic chip systems, which better emulate key hallmarks of human cancers. [5][6][7][8][9][10][11][12][13] Such platforms have undoubtedly opened a wide range of opportunities for recapitulating tumor biomolecular signatures, unravel intricate cell-cell interplays, and modulate different TME components (i.e., cell populations and the supportive tumor ECM). Despite their major contribution for improving preclinical drug screening, current 3D models ability for seamlessly mimicking human tumor specific bioarchitecture, namely the differential cells and ECM spatial organization is still limited and underexplored.…”

“…[5] These platforms were highly robust in mirroring the desmoplastic reaction, stratified architecture and drug resistance in a controlled laboratory setting. [5] Yet, the development of living pancreatic cancer models comprising pre-existing ECM components, namely tumor-specific and Scheme 1. Infographic of pancreatic cancer-on-a-bead technology that operates as a physiomimetic in vitro model to recapitulate major pancreatic cancer tumor microenvironment hallmarks.…”

“…[ 24 ] Recently, we generated heterotypic 3D PDAC stratified microenvironment spheroid models—so termed STAMS—comprising pancreatic cancer cells and CAFs organized in a stratified mode aiming to reproduce PDAC niche key signatures. [ 5 ] These platforms were highly robust in mirroring the desmoplastic reaction, stratified architecture and drug resistance in a controlled laboratory setting. [ 5 ] Yet, the development of living pancreatic cancer models comprising pre‐existing ECM components, namely tumor‐specific and stroma‐specific ECM in a relevant stratified spatial organization remains to be addressed.…”

“…[ 5 ] These platforms were highly robust in mirroring the desmoplastic reaction, stratified architecture and drug resistance in a controlled laboratory setting. [ 5 ] Yet, the development of living pancreatic cancer models comprising pre‐existing ECM components, namely tumor‐specific and stroma‐specific ECM in a relevant stratified spatial organization remains to be addressed.…”