ABSTRACT
In 3D cultured cell systems, the cells form 3D spheroids that mimic cancer cell spheroids in vivo. Cancer cells form cell spheroids as they grow. The in vivo spheroids do not contain a vascular network; therefore, oxygen and nutrition supplies are insufficient. Specifically, the cells in the core region of the cluster are exposed to higher stress levels than the cells in the outer spheroid layer. As a result, the cells in the spheroid are exposed to low nutrition and hypoxia conditions. To overcome these shortages, angiogenesis is induced in cancer spheroids in vivo. Vascular endothelial growth factor (VEGF) is an important molecule involved in angiogenesis. VEGF is secreted by cancer cells in vivo in response to stress conditions such as hypoxia. VEGF expression in cancer cells is mediated by hypoxia-inducible factor 1α (HIF1α), which accumulates in cancer cells during hypoxia. In this report, we show that VEGF expression is regulated by HIF1α and that VEGF is secreted to the outside of the spheroid in vitro. Several investigators have reported that HIF1α forms a protein-protein complex with aryl hydrocarbon receptor translocator (ARNT). We report here that not only HIF1α but also ARNT regulates VEGF expression in 3D cancer spheroids. Our results suggest the utility of the in vitro 3D cancer spheroid model for investigating angiogenesis in cancerous tissues.
Subject(s)
Aryl Hydrocarbon Receptor Nuclear Translocator/metabolism , Carcinoma, Squamous Cell/metabolism , Esophageal Neoplasms/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Vascular Endothelial Growth Factor A/biosynthesis , Aryl Hydrocarbon Receptor Nuclear Translocator/genetics , Carcinoma, Squamous Cell/blood supply , Carcinoma, Squamous Cell/genetics , Carcinoma, Squamous Cell/pathology , Cell Hypoxia/physiology , Cell Line, Tumor , Esophageal Neoplasms/blood supply , Esophageal Neoplasms/genetics , Esophageal Neoplasms/pathology , Esophageal Squamous Cell Carcinoma , Gene Knockdown Techniques , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Neovascularization, Pathologic/genetics , Neovascularization, Pathologic/metabolism , RNA, Small Interfering/administration & dosage , RNA, Small Interfering/genetics , Spheroids, Cellular , Transcription, Genetic , Vascular Endothelial Growth Factor A/geneticsABSTRACT
Pancreatobiliary maljunction (PBM) is a rare congenital malformation, often associated with adenocarcinoma. However, PBM accompanying gallbladder carcinosarcoma has rarely been reported. A 72-year-old woman was referred to our hospital, complaining of abdominal pain. Computed tomography showed a polypoid mass in the gallbladder. Endoscopic retrograde cholangiopancreatography showed PBM, and aspirated bile demonstrated elevated levels of pancreatic-type amylase (26,780 U/L) and cancer cells. Extended cholecystectomy was performed. Histologically, the tumor had adenocarcinoma, squamous cell carcinoma and sarcoma components. Despite the large tumor size (84 mm) and intra-vessel cancer permeations, this patient has been healthy for 73 months since the surgery.