ABSTRACT
Despite biomarker stratification, the anti-EGFR antibody cetuximab is only effective against a subgroup of colorectal cancers (CRCs). This genomic and transcriptomic analysis of the cetuximab resistance landscape in 35 RAS wild-type CRCs identified associations of NF1 and non-canonical RAS/RAF aberrations with primary resistance and validated transcriptomic CRC subtypes as non-genetic predictors of benefit. Sixty-four percent of biopsies with acquired resistance harbored no genetic resistance drivers. Most of these had switched from a cetuximab-sensitive transcriptomic subtype at baseline to a fibroblast- and growth factor-rich subtype at progression. Fibroblast-supernatant conferred cetuximab resistance in vitro, confirming a major role for non-genetic resistance through stromal remodeling. Cetuximab treatment increased cytotoxic immune infiltrates and PD-L1 and LAG3 immune checkpoint expression, potentially providing opportunities to treat cetuximab-resistant CRCs with immunotherapy.
Subject(s)
Colorectal Neoplasms/etiology , Drug Resistance, Neoplasm/genetics , Gene Expression Regulation, Neoplastic/drug effects , Immunity , Transcriptome , Antineoplastic Agents, Immunological/pharmacology , Antineoplastic Agents, Immunological/therapeutic use , Biomarkers, Tumor , Biopsy , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/mortality , Colorectal Neoplasms/pathology , Computational Biology/methods , DNA Mutational Analysis , ErbB Receptors/antagonists & inhibitors , Gene Expression Profiling , Humans , Kaplan-Meier Estimate , Molecular Targeted Therapy , Mutation , Prognosis , Treatment OutcomeABSTRACT
Aggressive behaviours of solid tumours are highly influenced by the tumour microenvironment. Multiple signalling pathways can affect the normal function of stromal fibroblasts in tumours, but how these events are coordinated to generate tumour-promoting cancer-associated fibroblasts (CAFs) is not well understood. Here we show that stromal expression of Dickkopf-3 (DKK3) is associated with aggressive breast, colorectal and ovarian cancers. We demonstrate that DKK3 is a HSF1 effector that modulates the pro-tumorigenic behaviour of CAFs in vitro and in vivo. DKK3 orchestrates a concomitant activation of ß-catenin and YAP/TAZ. Whereas ß-catenin is dispensable for CAF-mediated ECM remodelling, cancer cell growth and invasion, DKK3-driven YAP/TAZ activation is required to induce tumour-promoting phenotypes. Mechanistically, DKK3 in CAFs acts via canonical Wnt signalling by interfering with the negative regulator Kremen and increasing cell-surface levels of LRP6. This work reveals an unpredicted link between HSF1, Wnt signalling and YAP/TAZ relevant for the generation of tumour-promoting CAFs.
Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Cancer-Associated Fibroblasts/metabolism , Heat Shock Transcription Factors/metabolism , Intercellular Signaling Peptides and Proteins/metabolism , Phosphoproteins/metabolism , Transcription Factors/metabolism , Adaptor Proteins, Signal Transducing/genetics , Animals , Cell Line , Cells, Cultured , Chemokines , Gene Expression Profiling , Heat Shock Transcription Factors/genetics , Humans , Intercellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins , Low Density Lipoprotein Receptor-Related Protein-6/genetics , Low Density Lipoprotein Receptor-Related Protein-6/metabolism , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice, Nude , Mice, Transgenic , Neoplasms/genetics , Neoplasms/metabolism , Neoplasms/pathology , Phosphoproteins/genetics , Trans-Activators , Transcription Factors/genetics , Transcriptional Coactivator with PDZ-Binding Motif Proteins , Wnt Signaling Pathway/genetics , beta Catenin/genetics , beta Catenin/metabolismABSTRACT
Metastasis is the main cause of cancer patient mortality. Local tumor invasion is a key step in metastatic dissemination whereby cancer cells dislodge from primary tumors, migrate through the peritumoral stroma and reach the circulation. This is a highly dynamic process occurring in three dimensions that involves interactions between tumor, stromal cells, and the extracellular matrix. Here we describe the organotypic culture system and its utility to study breast cancer cell invasion induced by cancer-associated fibroblasts. This is a three-dimensional model that reproduces the biochemical and physiological properties of real tissue and allows for investigating the molecular and cellular mechanisms involving tumor and its microenvironment, and their contribution to cancer cell invasion . This system provides a robust, accurate, and reproducible method for measuring cancer cell invasion and represents a valuable tool to improve the mechanistic understanding of the initial steps in metastasis .
Subject(s)
Breast Neoplasms/pathology , Cancer-Associated Fibroblasts/cytology , Coculture Techniques/methods , Organoids/cytology , Animals , Cancer-Associated Fibroblasts/pathology , Cell Line, Tumor , Female , Fibroblasts/pathology , Humans , Mice , Neoplasm Invasiveness , Stromal Cells/pathology , Tumor MicroenvironmentABSTRACT
Cancer-associated fibroblasts (CAFs) are non-cancerous cells found in solid tumors that remodel the tumor matrix and promote cancer invasion and angiogenesis. Here, we demonstrate that Cdc42EP3/BORG2 is required for the matrix remodeling, invasion, angiogenesis, and tumor-growth-promoting abilities of CAFs. Cdc42EP3 functions by coordinating the actin and septin networks. Furthermore, depletion of SEPT2 has similar effects to those of loss of Cdc42EP3, indicating a role for the septin network in the tumor stroma. Cdc42EP3 is upregulated early in fibroblast activation and precedes the emergence of the highly contractile phenotype characteristic of CAFs. Depletion of Cdc42EP3 in normal fibroblasts prevents their activation by cancer cells. We propose that Cdc42EP3 sensitizes fibroblasts to further cues-in particular, those activating actomyosin contractility-and thereby enables the generation of the pathological activated fibroblast state.