Enhancing liquid biopsy potential: The impact of the R3CE 3D culture platform.

Abstract

e15032 Background: The ability to expand and preserve tumor cells ex vivo has been an important aspect of cancer research, offering insights into tumor biology and the advancement of personalized therapies. However, expanding rare tumor cells, such as circulating tumor cells (CTCs) and needle biopsies, remains challenging. Methods: We present the R3CE (Reproducible, Rapid, Rare Cell Expansion) 3D culture platform, a novel system that enhances the conventional tissue culture plate with a coating of polyelectrolyte multilayer. This approach can reliably cultivate various tumor specimens, including CTCs, needle biopsies, and surgical tissues, into tumor spheroids. Results: Our platform achieved over a 90% success rate (n = 305) in producing tumor spheroids with uniform size and preserved mutational profiles across diverse cancer types such as breast, lung, and colorectal cancers. In comparison to traditional tissue biopsies, liquid biopsies are less invasive and contain CTCs that offer a more comprehensive representation of heterogeneous tumor cell populations. We show that the proliferative capacity of cultured CTCs, rather than the initial CTC counts, have a strong correlation with lung adenocarcinoma prognosis (n = 124), highlighting the clinical potential of the R3CE platform (1). Furthermore, we have successfully employed cultured CTCs for drug screening for various cancers (breast cancer, cholangiocarcinoma, colon cancer, EMPD, gastric cancer, hepatoma, lung cancer, mucosal melanoma, pancreatic cancer, and urinary bladder cancer, n = 80), resulting in measurement of ex vivo response to chemotherapy and targeted drugs. For instance, R3CE-cultured CTCs have been used in predicting response to neoadjuvant chemotherapeutic drugs in breast cancer, as evidenced by an ROC curve analysis with an AUC of 0.963, 100% sensitivity, 87.5% specificity, P=0.02. Also in an exploratory analysis of immunotherapy efficacy, involving co-culture of R3CE-cultured CTCs (n = 6) and tumor tissue-derived organoids (n = 6) with immune cells such as CAR-T and autologous NK cells, has shown promising outcomes for selected cancers. Conclusions: The R3CE 3D culture platform represents a potentially transformative tool above and beyond CTC enumeration, significantly enhancing 1) the expansion of tumor cells ex vivo and, more importantly, informing phenotypic and genotypic characterization of CTCs, thereby holding promise for advancing cancer care and treatment efficacy. 1. Che et al., Lung Cancer, 2023; 178:198-205.