Notch1 transactivates Notch3 to drive terminal differentiation in stratified squamous epithelia. Notch1 and other Notch receptor paralogs cooperate to act as a tumor suppressor in squamous cell carcinomas (SCCs). However, Notch1 can be stochastically activated to promote carcinogenesis in murine models of SCC. Activated form of Notch1 promotes xenograft tumor growth when expressed ectopically. Here, we demonstrate that Notch1 activation and epithelial–mesenchymal transition (EMT) are coupled to promote SCC tumor initiation in concert with transforming growth factor (TGF)-β present in the tumor microenvironment. We find that TGFβ activates the transcription factor ZEB1 to repress Notch3, thereby limiting terminal differentiation. Concurrently, TGFβ drives Notch1-mediated EMT to generate tumor initiating cells characterized by high CD44 expression. Moreover, Notch1 is activated in a small subset of SCC cells at the invasive tumor front and predicts for poor prognosis of esophageal SCC, shedding light upon the tumor promoting oncogenic aspect of Notch1 in SCC.
The tumor microenvironment (TME) plays a major role in the pathogenesis of multiple cancer types, including upper-gastrointestinal (GI) cancers that currently lack effective therapeutic options. Cancer-associated fibroblasts (CAF) are an essential component of the TME, contributing to tumorigenesis by secreting growth factors, modifying the extracellular matrix, supporting angiogenesis, and suppressing antitumor immune responses. Through an unbiased approach, we have established that IL-6 mediates cross-talk between tumor cells and CAF not only by supporting tumor cell growth, but also by promoting fibroblast activation. As a result, IL-6 receptor (IL6Rα) and downstream effectors offer opportunities for targeted therapy in upper-GI cancers. IL-6 loss suppressed tumorigenesis in physiologically relevant three-dimensional (3D) organotypic and 3D tumoroid models and murine models of esophageal cancer. Tocilizumab, an anti-IL6Rα antibody, suppressed tumor growth in part via inhibition of STAT3 and MEK/ERK signaling. Analysis of a pan-cancer TCGA dataset revealed an inverse correlation between IL-6 and IL6Rα overexpression and patient survival. Therefore, we expanded evaluation of tocilizumab to head and neck squamous cell carcinoma patient-derived xenografts and gastric adenocarcinoma xenografts, demonstrating suppression of tumor growth and altered STAT3 and ERK1/2 gene signatures. We used small-molecule inhibitors of STAT3 and MEK1/2 signaling to suppress tumorigenesis in the 3D organotypic model of esophageal cancer. We demonstrate that IL6 is a major contributor to the dynamic cross-talk between tumor cells and CAF in the TME. Our findings provide a translational rationale for inhibition of IL6Rα and downstream signaling pathways as a novel targeted therapy in oral-upper-GI cancers. These findings demonstrate the interaction of esophageal cancer and cancer-associated fibroblasts through IL-6 signaling, providing rationale for a novel therapeutic approach to target these cancers. .
Background & AimsOropharyngeal and esophageal squamous cell carcinomas, especially the latter, are a lethal disease, featuring intratumoral cancer cell heterogeneity and therapy resistance. To facilitate cancer therapy in personalized medicine, three-dimensional (3D) organoids may be useful for functional characterization of cancer cells ex vivo. We investigated the feasibility and the utility of patient-derived 3D organoids of esophageal and oropharyngeal squamous cell carcinomas.MethodsWe generated 3D organoids from paired biopsies representing tumors and adjacent normal mucosa from therapy-naïve patients and cell lines. We evaluated growth and structures of 3D organoids treated with 5-fluorouracil ex vivo.ResultsTumor-derived 3D organoids were grown successfully from 15 out of 21 patients (71.4%) and passaged with recapitulation of the histopathology of the original tumors. Successful formation of tumor-derived 3D organoids was associated significantly with poor response to presurgical neoadjuvant chemotherapy or chemoradiation therapy in informative patients (P = 0.0357, progressive and stable diseases, n = 10 vs. partial response, n = 6). The 3D organoid formation capability and 5-fluorouracil resistance were accounted for by cancer cells with high CD44 expression and autophagy, respectively. Such cancer cells were found to be enriched in patient-derived 3D organoids surviving 5-fluorouracil treatment.ConclusionsThe single cell-based 3D organoid system may serve as a highly efficient platform to explore cancer therapeutics and therapy resistance mechanisms in conjunction with morphological and functional assays with implications for translation in personalized medicine.
Objectives/Hypothesis Delineate factors impacting creation and use of patient-derived xenografts (PDXs) of human papilloma virus-related (HPV+) head and neck squamous cell carcinomas (HNSCCs). Study Design Laboratory-based translational study. Methods 51 surgically resected HNSCCs, including 31 HPV+ cancers, were implanted into NOD/SCID/IL-2Rγ−/− (NSG) mice using standardized methodology. Clinical and pathologic factors were tested for association with engraftment. The gross, histologic, and molecular features of established HPV+ PDXs were analyzed in comparison to their tumors of origin. Results Negative HPV status and perineural invasion (PNI) were independent, additive factors associated with increased PDX formation. Epstein-Barr Virus-positive (EBV+) human large B-cell lymphomas grew from 32% of HPV+ HNSCC cases that failed to engraft. Successfully established HPV+ PDXs retained basaloid histology and often developed cystic growth patterns typical of HPV+ nodal metastases. They also maintained elevated p16INK4A levels and expression of E6/E7 viral oncogene transcripts. Conclusion Reduced engraftment by HPV+ tumors lacking PNI likely results in selection biases in HNSCC PDX models. Formation of EBV+ lymphomas in NSG mice further reduces generation of HPV+ models and must be ruled out before long-term use of PDXs. Nevertheless, retention of distinctive pathologic traits and viral oncogene expression by HPV+ PDXs provides a viable in vivo platform for basic and translational studies as well as a resource for generating advanced in vitro models.
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