title: A systematic analysis reveals heterogeneous changes in the endocytic activities of cancer cells.
abstract: Metastasis is a multistep process requiring cancer cell signaling, invasion, migration, survival, and proliferation. These processes require dynamic modulation of cell surface proteins by endocytosis. Given this functional connection, it has been suggested that endocytosis is dysregulated in cancer. To test this, we developed In-Cell ELISA assays to measure three different endocytic pathways: clathrin-mediated endocytosis, caveolae-mediated endocytosis, and clathrin-independent endocytosis and compared these activities using two different syngeneic models for normal and oncogene-transformed human lung epithelial cells. We found that all endocytic activities were reduced in the transformed versus normal counterparts. However, when we screened 29 independently isolated non-small cell lung cancer (NSCLC) cell lines to determine whether these changes were systematic, we observed significant heterogeneity. Nonetheless, using hierarchical clustering based on their combined endocytic properties, we identified two phenotypically distinct clusters of NSCLCs. One co-clustered with mutations in KRAS, a mesenchymal phenotype, increased invasion through collagen and decreased growth in soft agar, whereas the second was enriched in cells with an epithelial phenotype. Interestingly, the two clusters also differed significantly in clathrin-independent internalization and surface expression of CD44 and CD59. Taken together, our results suggest that endocytotic alterations in cancer cells that affect cell surface expression of critical molecules have a significant influence on cancer-relevant phenotypes, with potential implications for interventions to control cancer by modulating endocytic dynamics.
authors.affiliation: Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas.
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Elkin
authors.affiliation: Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas.
authors.forename: Nawal
authors.initials: N
authors.lastname: Bendris
authors.affiliation: Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Reis
authors.affiliation: Department of Clinical Science and Quantitative Biomedical Research Center (QBRC), UT Southwestern Medical Center, Dallas, Texas.
authors.forename: Yunyun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Clinical Science and Quantitative Biomedical Research Center (QBRC), UT Southwestern Medical Center, Dallas, Texas.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xie
authors.affiliation: The Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, Texas.
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Huffman
authors.affiliation: The Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, Texas. Departments of Internal Medicine and Pharmacology, UT Southwestern Medical Center, Dallas, Texas.
authors.forename: John D
authors.initials: JD
authors.lastname: Minna
authors.affiliation: Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas. Sandra.Schmid@utsouthwestern.edu.
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Schmid
mesh_terms: D018957:CD59 Antigens / Q000096:biosynthesis; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology; D021941:Caveolae / Q000378:metabolism; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D049109:Cell Proliferation; D002966:Clathrin / Q000378:metabolism; D003094:Collagen / Q000235:genetics; D004705:Endocytosis; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D009361:Neoplasm Invasiveness; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics; D020545:Respiratory Mucosa / Q000378:metabolism / Q000473:pathology
chemical_list: C497483:CD44 protein, human; D018957:CD59 Antigens; D002966:Clathrin; D018960:Hyaluronan Receptors; C117307:KRAS protein, human; C051590:CD59 protein, human; D003094:Collagen; D016283:Proto-Oncogene Proteins p21(ras)