Induction of dormancy by confinement: An agarose‐silica biomaterial for isolating and analyzing dormant cancer cells

Abstract

The principal cause of cancer deaths is the residual disease, which eventually results in metastases. Certain metastases are induced by disseminated dormancy-capable single cancer cells that can reside within the body undetected for months to years. Awakening of the dormant cells starts a cascade resulting in the patient's demise. Despite its established clinical significance, dormancy research and its clinical translation have been hindered by lack of in vitro models that can identify, isolate, and analyze dormancycapable cells. We have previously shown that immobilization of cells in a stiff microenvironment induces dormancy in dormancy-capable cell lines. In this communication, we present a novel biomaterial and an in vitro immobilization method to isolate, analyze, and efficiently recover dormancy-capable cancer cells. MCF-7, MDA-MB-231, and MDA-MB-468 cells were individually coated with agarose using a microfluidic flowfocusing device. Coated cells were then immobilized in a rigid and porous silica gel. Dormancy induction by this process was validated by decreased Ki-67 expression, increased p38/ERK activity ratio, and reduced expression of CDK-2, cyclins D1, and E1.We showed that we can reliably and repeatedly induce dormancy in dormancy-capable MCF-7 cells and enhance the dormancy-capable sub-population in MDA-MB-231 cells.As expected, dormancy-resistant MDA-MB-468 cells did not survive immobilization.The dormant cells could be awakened on demand, by digesting the agarose gel in situ, and efficiently recovered by magnetically separating the silica gel, making the cells available for downstream analysis and testing. The awakened cells were shown to regain motility immediately, proliferating, and migrating normally.

Pancreatic Ductal Adenocarcinoma Cortical Mechanics and Clinical Implications

“…Ongoing research is developing ways to induce cancer cells to exit dormancy by using biomaterials. Using an agarose-silica gel-based method, breast cancer cells were able to enter dormant states and then exit by immediately regaining proliferative and migratory capabilities that were lost in the dormant state ( 134 ). Uncovering the mechanism of matrix stiffness regulating dormancy will provide new insight on how to effectively target dormant cancer cells and prevent clinical relapse.…”

Magnetically‐actuated microcages for cells entrapment, fabricated by laser direct writing via two photon polymerization

“…For example, restraining the cells attachment to certain surfaces, directing cells growth and inducing cells differentiation are some of the main goals in designing complex 3D architectures for biomedical applications ( Liao et al, 2020 ; Paun et al, 2020a ; Sharaf et al, 2022 ). Until present, different cells entrapment techniques have been extensively studied regarding their ability to immobilize cells in different pathologies, such as cancer metastasis ( Ju et al, 2020 ; Preciado et al, 2021 ), microbial infections ( Li et al, 2021a ) or inflammation ( Schmidt and Wittrup, 2009 ), etc., as well as for tissue engineering applications (Khetan et al, 2009; Guvendiren and Burdick, 2012 ) or for “cell delivery” applications ( Gatto et al, 2023 ).…”