Purpose We undertook this study to determine the prevalence of estrogen receptor (ER) α (ESR1) mutations throughout the natural history of hormone dependent breast cancer and to delineate the functional roles of the most commonly detected alterations. Experimental Design We studied a total of 249 tumor specimens from 208 patients. The specimens include 134 ER positive (ER+/HER2–) and, as controls, 115 ER negative (ER−) tumors. The ER+ samples consist of 58 primary breast cancers and 76 metastatic samples. All tumors were sequenced to high unique coverage using next generation sequencing targeting the coding sequence of the estrogen receptor and an additional 182 cancer-related genes. Results Recurring somatic mutations in codons 537 and 538 within the ligand-binding domain of ER were detected in ER+ metastatic disease. Overall, the frequency of these mutations was 12% (9/76, 95% CI 6%-21%) in metastatic tumors and in a subgroup of patients who received an average of 7 lines of treatment the frequency was 20% (5/25, 95% CI 7%-41%). These mutations were not detected in primary or treatment naïve ER+ cancer or in any stage of ER− disease. Functional studies in cell line models demonstrate that these mutations render estrogen receptor constitutive activity and confer partial resistance to currently available endocrine treatments. Conclusions In this study we show evidence for the temporal selection of functional ESR1 mutations as potential drivers of endocrine resistance during the progression of ER positive breast cancer.

Background. Intrahepatic cholangiocarcinoma (ICC) is a subtype of primary liver cancer that is rarely curable by surgery and is rapidly increasing in incidence. Relapsed ICC has a poor prognosis, and current systemic nontargeted therapies are commonly extrapolated from those used in other gastrointestinal malignancies. We hypothesized that genomic profiling of clinical ICC samples would identify genomic alterations that are linked to targeted therapies and that could facilitate a personalized approach to therapy. Methods. DNA sequencing of hybridization-captured libraries was performed for 3,320 exons of 182 cancer-related genes and 36 introns of 14 genes frequently rearranged in cancer. Sample DNA was isolated from 40 mm of 28 formalin-fixed paraffin-embedded ICC specimens and sequenced to high coverage.

contributed equally to this work Clathrin-coated pits at the cell surface select material for transportation into the cell interior. A major mode of cargo selection at the bud site is via the m2 subunit of the AP-2 adaptor complex, which recognizes tyrosine-based internalization signals. Other internalization motifs and signals, including phosphorylation and ubiquitylation, also tag certain proteins for incorporation into a coated vesicle, but the mechanism of selection is unclear. Disabled-2 (Dab2) recognizes the FXNPXY internalization motif in LDL-receptor family members via an N-terminal phosphotyrosinebinding (PTB) domain. Here, we show that in addition to binding AP-2, Dab2 also binds directly to phosphoinositides and to clathrin, assembling triskelia into regular polyhedral coats. The FXNPXY motif and phosphoinositides contact different regions of the PTB domain, but can stably anchor Dab2 to the membrane surface, while the distal AP-2 and clathrin-binding determinants regulate clathrin lattice assembly. We propose that Dab2 is a typical member of a growing family of cargo-speci®c adaptor proteins, including b-arrestin, AP180, epsin, HIP1 and numb, which regulate clathrin-coat assembly at the plasma membrane by synchronizing cargo selection and lattice polymerization events.

Epsin 1 engages several core components of the endo-cytic clathrin coat, yet the precise mode of operation of the protein remains controversial. The occurrence of tandem ubiquitin-interacting motifs (UIMs) suggests that epsin could recognize a ubiquitin internalization tag, but the association of epsin with clathrin-coat components or monoubiquitin is reported to be mutually exclusive. Here, we show that endogenous epsin 1 is clearly an integral component of clathrin coats forming at the cell surface and is essentially absent from caveolin-1-containing structures under normal conditions. The UIM region of epsin 1 associates directly with poly-ubiquitin chains but has extremely poor affinity for monoubiquitin. Polyubiquitin binding is retained when epsin synchronously associates with phosphoinositides, the AP-2 adaptor complex and clathrin. The enrichment of epsin within clathrin-coated vesicles purified from different tissue sources varies and correlates with sorting of multiubiquitinated cargo, and in cultured cells, polyubi-quitin, rather than non-conjugable monoubiquitin, promotes rapid internalization. As epsin interacts with eps15, which also contains a UIM region that binds to polyubiquitin, epsin and eps15 appear to be central components of the vertebrate poly/multiubiquitin-sorting endocytic clathrin machinery. Clathrin-mediated endocytosis governs not only the routine uptake of membrane and nutrient receptors but also promotes the internalization of several ligand-stimulated receptors, ion channels and transporters (1). Selection of designated cargo depends upon appropriately positioned peptide internalization motifs or signals that are recognized by the protein components of the assembling cla-thrin lattice, retaining transmembrane cargo proteins at the bud site as invagination proceeds (2,3). Internalization signals were initially uncovered on analysis of a mutant low-density lipoprotein (LDL) receptor that contains a ]single amino acid substitution within the cytosolic domain (4). Although expressed at the cell surface, the Tyr807Cys substitution blocks the capacity of liganded LDL receptors to concentrate within clathrin-coated pits, preventing efficient LDL uptake and, ultimately, leading to pathological hypercholesterolemia (4). Further analysis of LDL receptor endocytosis defined the cytosolic 802 FXNPXY internal-ization motif as the critical determinant recognized by the clathrin-coat machinery (5). Several other transmembrane proteins, including the trans-ferrin and mannose 6-phosphate receptors, use an alternate Tyr-based internalization motif (2). On the basis of the consensus YXXØ, where Ø represents a residue with a bulky hydrophobic side chain, this sequence interacts directly with the m2 subunit of the plasma-membrane-specific heterote-trameric AP-2 adaptor complex (6). The molecular basis for this interaction has been resolved at the atomic level (7). Mutations that disrupt the binding of YXXØ sequences to m2, when inducibly expressed as a mutant m2 subunit in HeLa cells, potently block ...

Although urothelial carcinoma (UC) of the urinary bladder generally portends a favorable prognosis, metastatic tumors often follow an aggressive clinical course. DNA was extracted from 40 lm of formalin-fixed, paraffinembedded (FFPE) sections from 35 stage IV UCs that had relapsed and progressed after primary surgery and conventional chemotherapy. Next-generation sequencing (NGS) was performed on hybridization-captured, adaptor ligation-based libraries for 3320 exons of 182 cancer-related genes plus 37 introns from 14 genes frequently rearranged in cancer to at an average sequencing depth of 1164 Â and evaluated for all classes of genomic alterations (GAs). Actionable GAs were defined as those impacting the selection of targeted anticancer therapies on the market or in registered clinical trials. A total of 139 GAs were identified, with an average of 4.0 GAs per tumor (range 0-10), of which 78 (56%) were considered actionable, with an average of 2.2 per tumor (range 0-7). Twenty-nine (83%) cases harbored at least one actionable GA including: PIK3CA (9 cases; 26%); CDKN2A/B (8 cases; 23%); CCND1 (5 cases; 14%); FGFR1 (5 cases; 14%); CCND3 (4 cases; 11%); FGFR3 (4 cases; 11%); MCL1 (4 cases; 11%); MDM2 (4 cases; 11%); EGFR (2 cases, 6%); ERBB2 (HER2/neu) (2 cases, 6%); NF1 (2 cases, 6%) and TSC1 (2 cases, 6%). Notable additional alterations included TP53 (19 cases, 54%) and RB1 (6 cases; 17%). Genes involved in chromatin modification were altered by nonsense mutation, splice site mutation or frameshift indel in a mutually exclusive manner in nearly half of all cases including KDM6A (10 cases; 29%) and ARID1A (7 cases; 20%). Comprehensive NGS of 35 UCs of the bladder revealed a diverse spectrum of actionable GAs in 83% of cases, which has the potential to inform treatment decisions for patients with relapsed and metastatic disease.

BACKGROUND: Next-generation sequencing was performed on pulmonary and pancreatic fine-needle aspirations (FNAs) and on paired FNAs and resected primary tumors from the same patient. METHODS: DNA was isolated in formalin-fixed, paraffin-embedded cell blocks from 16 pulmonary FNAs, 23 pancreatic FNAs, and 5 resected pancreatic primary tumors.Next-generation sequencing was performed for 4561 exons of 287 cancer-related genes and for 47 introns of 19 genes on indexed, adaptor-ligated, hybridization-captured libraries using a proprietary sequencing system (the Illumina HiSeq 2000). RESULTS: Genomic profiles were generated successfully from 16 of 16 (100%) pulmonary FNAs, which included 14 nonsmall cell lung cancers (NSCLCs) and 2 small cell lung cancers (SCLCs). The NSCLC group included 6 adenocarcinomas, 5 squamous cell carcinomas, and 3 NSCLCs not otherwise specified. Genomic profiles were successfully obtained from 23 of 23 (100%) pancreatic FNAs and from 5 of 5 (100%) matched pancreatic primary tumors, which included 17 ductal adenocarcinomas, 3 mucinous adenocarcinomas, 2 adenocarcinomas NOS, and 1 neuroendocrine tumor. Eightyone genomic alterations were identified in the 16 pulmonary FNAs (average, 5.1 genomic alterations per patient); and the most common genomic alterations were TP53, RB1, SOX2, PIK3CA, and KRAS. Eighty-seven genomic alterations were identified in the 23 pancreatic tumor FNAs (average, 3.8 genomic alterations per patient); and the most common genomic alterations were KRAS, TP53, CDKN2A/B, SMAD4, and PTEN. Among the pancreatic tumors, there was 100% concordance of 20 genomic alterations that were identified in 5 patient-matched FNA and surgical primary tumor pairs. CONCLUSIONS:The authors were able to perform next-generation sequencing reliably on FNAs of pulmonary and pancreatic tumors, and the genomic alterations discovered correlated well with those identified in matched resected pancreatic tumors. Cancer (Cancer Cytopathol) 2013;121:688-94.

Purpose: Micropapillary urothelial carcinoma (MPUC) is a rare and aggressive form of bladder cancer. We conducted genomic analyses [next-generation sequencing (NGS)] of MPUC and non-micropapillary urothelial bladder carcinomas (non-MPUC) to characterize the genomic landscape and identify targeted treatment options.Experimental Design: DNA was extracted from 40 mm of formalin-fixed paraffin-embedded sections from 15 MPUC and 64 non-MPUC tumors. Sequencing (NGS) was performed on hybridization-captured, adaptor ligation-based libraries to high coverage for 3,230 exons of 182 cancer-related genes plus 37 introns from 14 genes frequently rearranged in cancer. The results were evaluated for all classes of genomic alteration.Results: Mutations in the extracellular domain of ERBB2 were identified in 6 of 15 (40%) of MPUC: S310F (four cases), S310Y (one case), and R157W (one case). All six cases of MPUC with ERBB2 mutation were negative for ERBB2 amplification and Erbb2 overexpression. In contrast, 6 of 64 (9.4%) non-MPUC harbored an ERBB2 alteration, including base substitution (three cases), amplification (two cases), and gene fusion (one case), which is higher than the 2 of 159 (1.3%) protein-changing ERBB2 mutations reported for urinary tract cancer in COSMIC. The enrichment of ERBB2 alterations in MPUC compared with non-MPUC is significant both between this series (P < 0.0084) and for all types of urinary tract cancer in COSMIC (P < 0.001).Conclusions: NGS of MPUC revealed a high incidence of mutation in the extracellular domain of ERBB2, a gene for which there are five approved targeted therapies. NGS can identify genomic alteration, which inform treatment options for the majority of MPUC patients. Clin Cancer Res; 20(1); 68-75. Ó2013 AACR.

Clathrin-mediated endocytosis depends upon the coordinated assembly of a large number of discrete clathrin coat components to couple cargo selection with rapid internalization from the cell surface. Accordingly, the heterotetrameric AP-2 adaptor complex binds not only to clathrin and select cargo molecules, but also to an extensive family of endocytic accessory factors and alternate sorting adaptors. Physical associations between accessory proteins and AP-2 occur primarily through DP(F/W) or FXDXF motifs, which engage an interaction surface positioned on the C-terminal platform subdomain of the independently folded ␣ subunit appendage. Here, we find that the WXX(F/W)X(D/E) interaction motif found in several endocytic proteins, including synaptojanin 1, stonin 2, AAK1, GAK, and NE-CAP1, binds a second interaction site on the bilobal ␣ appendage, located on the N-terminal ␤ sandwich subdomain. Both ␣ appendage binding sites can be engaged synchronously, and our data reveal that varied assemblies of interaction motifs with different affinities for two sites upon the ␣ appendage can provide a mechanism for temporal ordering of endocytic accessory proteins during clathrin-mediated endocytosis.Clathrin-coated vesicles are a major portal of entry into eukaryotic cells, carrying macromolecular nutrients, ligands, select transmembrane proteins, and even viruses into the cell interior from the plasma membrane (1, 2). Cargo selectivity of these short-lived transport intermediates is often thought to be governed by a central triad of proteins, the cargo receptors, clathrin, and the heterotetrameric AP-2 adaptor complex. Cargo receptors contain cytosolic internalization sequences, such as the YXXØ motif (where X is any amino acid and Ø represents a residue with a bulky hydrophobic side chain), found within proteins like the receptor for the endocytosed iron transport protein transferrin. Several distinct internalization sequences or tags are known, each specifying internalization by promoting preferential incorporation into assembling clathrincoated vesicles (3). Clathrin functions as a trimer of heterodimers, composed of three 192-kDa heavy and three 20 -25-kDa light chains, that polymerize to form the characteristic polyhedral clathrin lattice (4,5). Assembled clathrin appears to act as a mechanical scaffold during the process of bud invagination. AP-2, the archetypical sorting adaptor, is composed of two large (ϳ100 kDa) subunits (␣ and ␤2), a 50-kDa medium 2 subunit, and a 17-kDa small 2 chain (2, 6). AP-2 binds physically to both clathrin, through the hinge and appendage domains of the ␤2 subunit (7), and to YXXØ-type internalization sequences, via the 2 subunit, in a phosphorylation-regulated manner (6, 8 -10). AP-2 is therefore a multifunctional protein that couples coat assembly with cargo selection. Surprisingly, after small interfering RNA silencing of either the AP-2 ␣ or 2 subunit mRNA in HeLa cells to deplete cellular AP-2 adaptor levels, certain transmembrane receptors, like the epidermal growth factor and low ...