The ATPase activity of ABCA1 is increased by cholesterol in the presence of anionic lipids.

High-density lipoprotein (HDL) transports excess cholesterol from peripheral tissues back to the liver, and plasma HDL levels are inversely related to cardiovascular disease incidence. ATP-binding cassette A1 (ABCA1) is a member of the ABC protein superfamily, and generates nascent HDL, which consists of several hundreds of phospholipids and cholesterol wrapped by apolipoprotein A-I (apoA-I). However, it remains unclear whether cholesterol is a transport substrate of ABCA1. Since ATP hydrolysis of ABC proteins is typically increased by their transport substrates, we characterized the effects of cholesterol on the ATPase activity of purified ABCA1 using liposomes of various lipid compositions. ABCA1 showed substantial ATPase activity (20-30 nmol$\cdot$min-1$\cdot$mg-1) only in liposomes containing anionic lipids, including phosphatidylserine. Cholesterol increased the ATPase activity by 1.6- to 3-fold in the presence of anionic lipids. Moreover, phosphatidylserine addition to BHK/ABCA1 cells increased phosphatidylcholine and cholesterol efflux to apoA-I. Next, we investigated the sterol specificity of ABCA1. The ATPase activity of ABCA1 was strongly enhanced by desmosterol and zymosterol, similar to cholesterol. In contrast, 7-dehydrocholesterol and lathosterol weakly increased the ATPase activity, and no increase was observed with stigmasterol or brassicasterol. These findings suggest that ABCA1 transports cholesterol and prefers cholesterol over plant sterols as a transport substrate.

Preoperative CA19-9 is a prognostic factor in pT3N0 gastric cancer patients undergoing curative resection.

BACKGROUND: The standard treatment for pT3N0 gastric cancer (GC) in Japanese guidelines is radical surgery without adjuvant chemotherapy. However, certain percentages of these patients develop recurrences; therefore, detecting the high-risk subgroup of recurrence may contribute to improve patient's outcome by adjuvant chemotherapy. In this study, we aimed to identify a predictive indicator of poor prognosis in pT3N0 GC. METHODS: Eighty-one patients who were diagnosed as pT3N0 GC after curative surgical resection and had not received adjuvant chemotherapy were included. The clinicopathological factors and laboratory parameters were evaluated by univariate and multivariate analyses to identify prognostic factors of tumor recurrence. Survival analysis was performed by Kaplan-Meier method. RESULTS: Male (P = 0.027), a high body mass index (BMI) (P = 0.031), a high CA19-9 value (P = 0.025), and a lower number of retrieved lymph nodes (P = 0.018) were found to be significantly associated with a shorter recurrence free survival (RFS). In a multivariate analysis, high CA19-9 value (> 37 U/ml) [(hazard ratio (HR): 3.326; 95% confidence interval (CI): 1.044 to 10.596; P = 0.042] was found to be an independent predictor of RFS. CONCLUSION: The preoperative high CA19-9 value is considered a useful prognostic marker for predicting cancer recurrence after curative surgery in pT3N0 GC patients. For those patients, adjuvant chemotherapy might be considered to improve the survival outcome.

ABCA13 dysfunction associated with psychiatric disorders causes impaired cholesterol trafficking.

ATP-binding cassette subfamily A member 13 (ABCA13) is predicted to be the largest ABC protein, consisting of 5058 amino acids and a long N-terminal region. Mutations in the ABCA13 gene were reported to increase the susceptibility to schizophrenia, bipolar disorder, and major depression. However, little is known about the molecular functions of ABCA13 or how they associate with psychiatric disorders. Here, we examined the biochemical activity of ABCA13 using HEK293 cells transfected with mouse ABCA13. The expression of ABCA13 induced the internalization of cholesterol and gangliosides from the plasma membrane to intracellular vesicles. Cholesterol internalization by ABCA13 required the long N-terminal region and ATP hydrolysis. To examine the physiological roles of ABCA13, we generated Abca13 KO mice using CRISPR/Cas and found that these mice exhibited deficits of prepulse inhibition. Vesicular cholesterol accumulation and synaptic vesicle endocytosis were impaired in primary cultures of Abca13 KO cortical neurons. Furthermore, mutations in ABCA13 gene associated with psychiatric disorders disrupted the protein's subcellular localization and impaired cholesterol trafficking. These findings suggest that ABCA13 accelerates cholesterol internalization by endocytic retrograde transport in neurons and that loss of this function is associated with the pathophysiology of psychiatric disorders.

ABCB1/MDR1/P-gp employs an ATP-dependent twist-and-squeeze mechanism to export hydrophobic drugs.

ABCB1, also called MDR1 or P-glycoprotein, exports various hydrophobic compounds and plays an essential role as a protective physiological barrier in several organs, including the brain, testis, and placenta. However, little is known about the structural mechanisms that allow ABCB1 to recognize hydrophobic compounds of diverse structures or the coupling of ATP hydrolysis to uphill substrate export. High-resolution X-ray crystal structures of the pre- and post-transport states and FRET analyses in living cells have revealed that an aromatic hydrophobic network at the top of the inner cavity is key for the conformational change in ABCB1 that is triggered by a hydrophobic substrate. ATP binding, but not hydrolysis, induces a progressive network that results in a twisting motion of the whole protein, squeezing out the substrate directly to the extracellular space. This twist-and-squeeze mechanism by which ABCB1 exports hydrophobic substrates is distinct from those of other transporters.

Preoperative prognostic nutritional index predicts risk of recurrence after curative resection for stage IIA colon cancer.

BACKGROUND: Preoperative nutritional and inflammatory indices have been reported to be associated with the prognosis of patients with malignancy. We evaluated clinicopathological factors, including nutritional and inflammatory indices, and recurrence prognosis in patients with stage IIA colon cancer (CC) who underwent curative surgery. METHODS: This retrospective study included 197 patients with stage IIA CC who had undergone curative resection. We evaluated the association between prognostic nutritional index (PNI), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) with clinicopathological factors and prognosis for recurrence. For the recurrence-free survival (RFS) analysis, receiver operating characteristic (ROC) curves were used to determine appropriate cutoff values for PNI, NLR, and PLR. RESULTS: Univariate analyses showed that PNI<44.8 (P = 0.028) was significantly associated with worse RFS in patients with stage IIA CC patients. In the multivariate analyses, PNI<44.8 (hazard ratio [HR] 2.082; 95% confidence interval [CI] 1.005-4.317; P = 0.049) independently and significantly predicted RFS. CONCLUSION: PNI is a useful marker for predicting recurrence prognosis in post-resection patients with stage IIA CC.

Predictive Effectiveness of the Glasgow Prognostic Score for Gastrointestinal Stromal Tumors.

The aim of this study was to evaluate the significance of the Glasgow prognostic score (GPS) in patients with resected gastrointestinal stromal tumors (GISTs). Forty-six GIST patients who underwent radical resection between January 2004 and December 2011 were enrolled in this retrospective study. The clinicopathological parameters examined included predictors of recurrence-free survival (RFS). Univariate and multivariate analysis of prognostic factors related to RFS were calculated using Cox proportional hazards model. The GPS classification system revealed 37 (80.4%), 6 (13.1%), and 3 (6.5%) patients with a GPS of 0, 1, and 2, respectively. Patients with GPS 1/2 had a significantly shorter RFS compared to those with GPS 0 (P = 0.01). The 3- and 5-year RFS rates for patients with GPS 0 were 94.0% and 90.9%, respectively, compared to 66.7% and 53.3%, respectively, for patients with GPS 1/2. Univariate analyses indicated that tumor size (P < 0.01), mitotic rate (P < 0.01), higher GPS (P < 0.01), and platelet count (P = 0.04) were prognostic factors for RFS; tumor size (P = 0.01) and GPS (P = 0.04) were independent prognostic factors in multivariate analysis. Preoperative high GPS were predictors of long-term prognosis in patients with resected GISTs.

In vivo FRET analyses reveal a role of ATP hydrolysis-associated conformational changes in human P-glycoprotein.

P-glycoprotein (P-gp; also known as MDR1 or ABCB1) is an ATP-driven multidrug transporter that extrudes various hydrophobic toxic compounds to the extracellular space. P-gp consists of two transmembrane domains (TMDs) that form the substrate translocation pathway and two nucleotide-binding domains (NBDs) that bind and hydrolyze ATP. At least two P-gp states are required for transport. In the inward-facing (pre-drug transport) conformation, the two NBDs are separated, and the two TMDs are open to the intracellular side; in the outward-facing (post-drug transport) conformation, the NBDs are dimerized, and the TMDs are slightly open to the extracellular side. ATP binding and hydrolysis cause conformational changes between the inward-facing and the outward-facing conformations, and these changes help translocate substrates across the membrane. However, how ATP hydrolysis is coupled to these conformational changes remains unclear. In this study, we used a new FRET sensor that detects conformational changes in P-gp to investigate the role of ATP binding and hydrolysis during the conformational changes of human P-gp in living HEK293 cells. We show that ATP binding causes the conformational change to the outward-facing state and that ATP hydrolysis and subsequent release of γ-phosphate from both NBDs allow the outward-facing state to return to the original inward-facing state. The findings of our study underscore the utility of using FRET analysis in living cells to elucidate the function of membrane proteins such as multidrug transporters.

A case of esophageal cancer complicated with methotrexate-related lymphoproliferative disorder.

A 69-year-old woman had been undergoing treatment with methotrexate for rheumatoid arthritis for 9 years. Because fever and right hypochondriac pain continued, she visited the nearby hospital. The enlargement of intraabdominal multiple lymph nodes was detected through abdominal computed tomography. Esophagogastroduodenoscopy showed a depressed lesion in the lower intrathoracic esophagus, and squamous cell carcinoma was diagnosed by a biopsy. Positron emission tomography-computed tomography showed a highly abnormal accumulation of lymph nodes, mainly in the upper abdomen, and some lymph nodes around the aorta. Suspecting methotrexate-lymphoproliferative disorder, we discontinued the oral administration of methotrexate. Multiple lymphadenopathy reduced by the withdrawal of the oral administration of methotrexate. We operated for esophageal cancer, and she was discharged on the 17th postoperative day. The postoperative pathological result showed moderately differentiated squamous cell carcinoma. Metastasis to the lymph nodes around the esophagus was observed, and the patient was diagnosed with T1b (SM3), N2 M0, Stage II cancer. Immunostaining showed enlarged lymph nodes composed of CD20-positive cells and with cells positive for EBV-encoded small RNA in situ hybridization. This case shows that patients with rheumatoid arthritis who are being administered methotrexate may have enlarged lymph nodes due to methotrexate-lymphoproliferative disorder.

Hepatectomy for rapidly growing solitary liver metastasis from non-small cell lung cancer: a case report.

BACKGROUND: Patients with liver metastasis from non-small lung cancer (NSCLC) usually have multiple metastases at other sites and thus rarely undergo liver surgery. We present a case involving successful resection of rapidly growing liver metastasis from squamous cell carcinoma of the lung. CASE PRESENTATION: A 74-year-old man had undergone left lower lobectomy for squamous cell carcinoma of the lung, which was diagnosed pathologically as stage IA. A computed tomography (CT) scan that was taken 12 months after lung resection showed an irregularly shaped mass lesion (size, 8.3 cm) in segment five of the liver. Retrospectively, the mass was identifiable on CT 6 months before this initial recognition. Although the lesion showed rapid growth, positron emission tomography and brain magnetic resonance imaging ruled out the possibility of other metastatic lesions. Therefore, we performed right hepatectomy 14 months after the initial lung surgery. The patient was pathologically diagnosed with liver metastasis from lung cancer and has remained free from recurrence 41 months after the liver surgery, without receiving any adjuvant chemotherapy. CONCLUSIONS: Although there is no reliable clinical indicator for selecting oligo-recurrence, hepatectomy could be an option for solitary liver metastasis from NSCLC for patients who are in good health.

Inward- and outward-facing X-ray crystal structures of homodimeric P-glycoprotein CmABCB1.

P-glycoprotein extrudes a large variety of xenobiotics from the cell, thereby protecting tissues from their toxic effects. The machinery underlying unidirectional multidrug pumping remains unknown, largely due to the lack of high-resolution structural information regarding the alternate conformational states of the molecule. Here we report a pair of structures of homodimeric P-glycoprotein: an outward-facing conformational state with bound nucleotide and an inward-facing apo state, at resolutions of 1.9 Å and 3.0 Å, respectively. Features that can be clearly visualized at this high resolution include ATP binding with octahedral coordination of Mg2+; an inner chamber that significantly changes in volume with the aid of tight connections among transmembrane helices (TM) 1, 3, and 6; a glutamate-arginine interaction that stabilizes the outward-facing conformation; and extensive interactions between TM1 and TM3, a property that distinguishes multidrug transporters from floppases. These structural elements are proposed to participate in the mechanism of the transporter.

Apolipoprotein A-I directly interacts with extracellular domain 1 of human ABCA1.

ATP-binding cassette transporter A1 (ABCA1) is critical for the generation of nascent high-density lipoprotein (HDL) and plays important roles in cholesterol homeostasis. ABCA1 has two large extracellular domains (ECDs), which may interact directly with apolipoprotein A-I (apoA-I). However, the molecular mechanisms underlying HDL formation and the importance of ABCA1-apoA-I interactions in HDL formation remain unclear. We investigated the ABCA1-apoA-I interaction in photo-activated crosslinking experiments using sulfo-SBED-labeled apoA-I. ApoA-I bound to cells expressing ABCA1, but not to untransfected cells or cells expressing non-functional ABCA1. Binding was inhibited by sulfo-SBED-labeled apoA-I, and crosslinking of sulfo-SBED-labeled apoA-I with ABCA1 was inhibited by non-labeled apoA-I, suggesting that sulfo-SBED-labeled apoA-I specifically binds and crosslinks with functional ABCA1. Proteolytic digestion of crosslinked ABCA1 revealed that apoA-I bound the N-terminal half of ABCA1, and that the first ECD of ABCA1 is an apoA-I binding site. Abbreviations: ABC: ATP-binding cassette; apoA-I: apolipoprotein A-I; ATP: adenosine triphosphate; CHAPS: 3-(3-cholamidepropyl)dimethylammonio-1- propanesulphonate; DTT: dithiothreitol; ECD: extra cellular domain; EDTA: ethylenediaminetetraacetic acid; GFP: green fluorescent protein; HA: hemagglutinin; HDL: high density lipoprotein; HEK: human embryonic kidney; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; sulfo-SBED: (sulfosuccinimidyl-2-[6-(biotinamido)-2-(p-azidobenzamido)hexanoamido] ethyl-1,3'-dithiopropionate; NHS-ester, N-hydroxysuccinimide-ester.

Vinexin family (SORBS) proteins regulate mechanotransduction in mesenchymal stem cells.

The stiffness of extracellular matrix (ECM) directs the differentiation of mesenchymal stem cells (MSCs) through the transcriptional co-activators Yes-associated protein (YAP) and transcriptional coactivator with a PDZ-binding motif (TAZ). Although a recent study revealed the involvement of vinexin α and CAP (c-Cbl-associated proteins), two of vinexin (SORBS) family proteins that bind to vinculin, in mechanosensing, it is still unclear whether these proteins regulate mechanotransduction and differentiation of MSCs. In the present study, we show that both vinexin α and CAP are necessary for the association of vinculin with the cytoskeleton and the promotion of YAP/TAZ nuclear localization in MSCs grown on rigid substrates. Furthermore, CAP is involved in the MSC differentiation in a stiffness-dependent manner, whereas vinexin depletion suppresses adipocyte differentiation independently of YAP/TAZ. These observations reveal a critical role of vinexin α and CAP in mechanotransduction and MSC differentiation.

Leishmania LABCG2 transporter is involved in ATP-dependent transport of thiols.

The Leishmania LABCG2 transporter has a key role in the redox metabolism of these protozoan parasites. Recently, the involvement of LABCG2 in virulence, autophagy and oxidative stress has been described. Null mutant parasites for LABCG2 present an increase in the intracellular levels of glutathione (GSH) and trypanothione [T(SH)2]. On the other hand, parasites overexpressing LABCG2 transporter export non-protein thiols to the extracellular medium. To explore if LABCG2 may mediate an active transport of non-protein thiols, the effect of these molecules on ATPase activity of LABCG2 as well as the ability of LABCG2 to transport them was determined using a baculovirus-Sf9 insect cell system. Our results indicate that all thiols tested [GSH, T(SH)2] as well as their oxidized forms GSSG and TS2 (trypanothione disulfide) stimulate LABCG2-ATPase basal activity. We have measured the transport of [3H]-GSH in inside-out Sf9 cell membrane vesicles expressing LABCG2-GFP (green fluorescence protein), finding that LABCG2 was able to mediate a rapid and concentration-dependent uptake of [3H]-GSH in the presence of ATP. Finally, we have analyzed the ability of different thiol species to compete for this uptake, T(SH)2 and TS2 being the best competitors. The IC50 value for [3H]-GSH uptake in the presence of increasing concentrations of T(SH)2 was less than 100 µM, highlighting the affinity of this thiol for LABCG2. These results provide the first direct evidence that LABCG2 is an ABC transporter of reduced and oxidized non-protein thiols in Leishmania, suggesting that this transporter can play a role in the redox metabolism and related processes in this protozoan parasite.

Vinculin promotes nuclear localization of TAZ to inhibit ECM stiffness-dependent differentiation into adipocytes.

Extracellular matrix (ECM) stiffness regulates the lineage commitment of mesenchymal stem cells (MSCs). Although cells sense ECM stiffness through focal adhesions, how cells sense ECM stiffness and regulate ECM stiffness-dependent differentiation remains largely unclear. In this study, we show that the cytoskeletal focal adhesion protein vinculin plays a critical role in the ECM stiffness-dependent adipocyte differentiation of MSCs. ST2 mouse MSCs differentiate into adipocytes and osteoblasts in an ECM stiffness-dependent manner. We find that a rigid ECM increases the amount of cytoskeleton-associated vinculin and promotes the nuclear localization and activity of the transcriptional coactivator paralogs Yes-associated protein (YAP, also known as YAP1) and transcriptional coactivator with a PDZ-binding motif (TAZ, also known as WWTR1) (hereafter YAP/TAZ). Vinculin is necessary for enhanced nuclear localization and activity of YAP/TAZ on the rigid ECM but it does not affect the phosphorylation of the YAP/TAZ kinase LATS1. Furthermore, vinculin depletion promotes differentiation into adipocytes on rigid ECM, while it inhibits differentiation into osteoblasts. Finally, TAZ knockdown was less effective at promoting adipocyte differentiation in vinculin-depleted cells than in control cells. These results suggest that vinculin promotes the nuclear localization of transcription factor TAZ to inhibit the adipocyte differentiation on rigid ECM.

A Synthetic Hybrid Molecule for the Selective Removal of Human Pluripotent Stem Cells from Cell Mixtures.

A major hurdle in stem cell therapy is the tumorigenic risk of residual undifferentiated stem cells. This report describes the design and evaluation of synthetic hybrid molecules that efficiently reduce the number of human induced pluripotent stem cells (hiPSCs) in cell mixtures. The design takes advantage of Kyoto probe 1 (KP-1), a fluorescent chemical probe for hiPSCs, and clinically used anticancer drugs. Among the KP-1-drug conjugates we synthesized, we found an exceptionally selective, chemically tractable molecule that induced the death of hiPSCs. Mechanistic analysis suggested that the high selectivity originates from the synergistic combination of transporter-mediated efflux and the cytotoxicity mode of action. The present study offers a chemical and mechanistic rationale for designing selective, safe, and simple reagents for the preparation of non-tumorigenic clinical samples.

Giant insulinoma: report of a case and review of published reports.

BACKGROUND: Larger insulinomas are reportedly more likely to be malignant; however, their biological behavior has not been clearly elucidated. We here report the characteristics and treatment of a giant insulinoma with local invasion and lymph node metastasis. We also review published reports concerning the clinical features of giant insulinomas and comparing their grading with that of pancreatic neuroendocrine tumors. CASE PRESENTATION: A 71-year-old man was referred to our hospital for investigation of persistent hypoglycemia. On the current presentation, laboratory tests showed serum glucose, immunoreactive insulin, and C peptide concentrations of 45 mg/dL, 17.2 µIU/mL and 4.1 ng/mL, respectively. Dynamic magnetic resonance imaging showed a hypervascular tumor measuring 13.5 cm in the head of the pancreas. Computed tomography scanning demonstrated local invasion and lymph node involvement. He thus had Whipple's triad, which is associated with malignant insulinoma. No distant metastases having been identified, pancreaticoduodenectomy was performed. Intraoperatively, three separate tumors were identified in the pancreatic head. Pathological examination showed all three tumors were pancreatic neuroendocrine tumors; the tumor cells in the largest mass were strongly immunoreactive for insulin. The Ki-67 index was 2-5% in most parts of the largest tumor and over 20% in the poorly differentiated areas. This tumor was classified as neuroendocrine carcinoma in accordance with the 2010 World Health Organization classification of pancreatic endocrine neoplasms. He remains free of evidence of recurrence 2 years postsurgery. A review of published reports indicated that giant insulinomas are more malignant than smaller ones, and metastatic disease is found on presentation in 56% of patients with giant insulinomas; however, we were unable to identify any correlation between grade of pancreatic neuroendocrine tumor and biological behavior of giant insulinomas. CONCLUSIONS: Giant insulinomas more frequently exhibit malignant behavior, such as local invasion, lymph node involvement, and liver metastasis, than smaller ones. However, there was no relationship between grade and rate of metastases or survival in this small case series. Identification of useful biological markers is necessary.

Primary gastrointestinal stromal tumor of the liver: a case report and review of the literature.

BACKGROUND: Recently, gastrointestinal stromal tumors that have developed outside of the digestive tract have been reported. These tumors are collectively termed extra-gastrointestinal stromal tumors. Extra-gastrointestinal stromal tumors can also develop in the liver. Only eight case reports involving primary GIST of the liver have been published. We report a case and review the literature regarding this disease. CASE PRESENTATION: A 70-year-old woman with a past history of gastric cancer visited our hospital for regular inspection. With extensive radiological imaging, a computed tomography scan revealed a mass with a size of 6.8 cm in the lateral segment of the liver. (18)F-Fluoro-2-deoxyglucose positron emission tomography revealed no other malignancies except for the liver tumor. Because the lesion was suspected of being a primary malignant hepatic tumor, lateral segmentectomy was performed. The immunohistochemical analysis supported the diagnosis of gastrointestinal stromal tumors in the liver. The patient has had no evidence of recurrence during the 10-month follow-up period; imatinib chemotherapy was not administered. CONCLUSIONS: Primary hepatic gastrointestinal stromal tumors had no characteristics that distinguished them from ordinary tumors in imaging examinations. Primary gastrointestinal stromal tumors might have developed from interstitial Cajal-like cells.

ABCG1 and ABCG4 Suppress γ-Secretase Activity and Amyloid ß Production.

ATP-binding cassette G1 (ABCG1) and ABCG4, expressed in neurons and glia in the central nervous system, mediate cholesterol efflux to lipid acceptors. The relationship between cholesterol level in the central nervous system and Alzheimer's disease has been reported. In this study, we examined the effects of ABCG1 and ABCG4 on amyloid precursor protein (APP) processing, the product of which, amyloid ß (Aß), is involved in the pathogenesis of Alzheimer's disease. Expression of ABCG1 or ABCG4 in human embryonic kidney 293 cells that stably expressed Swedish-type mutant APP increased cellular and cell surface APP levels. Products of cleavage from APP by α-secretase and by ß-secretase also increased. The levels of secreted Aß, however, decreased in the presence of ABCG1 and ABCG4, but not ABCG4-KM, a nonfunctional Walker-A lysine mutant. In contrast, secreted Aß levels increased in differentiated SH-SY5Y neuron-like cells in which ABCG1 and ABCG4 were suppressed. Furthermore, Aß42 peptide in the cerebrospinal fluid from Abcg1 null mice significantly increased compared to the wild type mice. To examine the underlying mechanism, we analyzed the activity and distribution of γ-secretase. ABCG1 and ABCG4 suppressed γ-secretase activity and disturbed γ-secretase localization in the raft domains where γ-secretase functions. These results suggest that ABCG1 and ABCG4 alter the distribution of γ-secretase on the plasma membrane, leading to the decreased γ-secretase activity and suppressed Aß secretion. ABCG1 and ABCG4 may inhibit the development of Alzheimer's disease and can be targets for the treatment of Alzheimer's disease.

[Study of the Postoperative Adjuvant Chemotherapy with UFT/LV or Capecitabine for Stage III Colorectal Cancer].

OBJECTIVE: This study sought to compare UFT/LV with capecitabine as adjuvant chemotherapy for the treatment of stage III colorectal cancer. METHODS: We conducted a retrospective analysis of patients with Stage III colorectal cancer who underwent surgical resection, except low rectal resections (Rb), followed by adjuvant chemotherapy with UFT/LV or capecitabine between 2007 and 2009, and evaluated background factors, adverse event profiles, disease free survival (DFS), and overall survival (OS). RESULTS: The analysis included 39 patients treated with UFT/LV and 29 with capecitabine, with no significant differences observed between the groups in terms of gender, age, or disease Stage. The most common adverse events were gastrointestinal symptoms in the UFT/LV group, and hand-foot syndrome in the capecitabine group. The 3-year DFS was 69.2 and 64.7% in the UFT/LV and capecitabine groups respectively, and 3-year OS was 89.7 and 92.7% in the UFT/LV and capecitabine groups respectively, indicating no significant differences between the groups. CONCLUSION: There were no marked differences in treatment outcomes with UFT/LV or capecitabine when they were used as adjuvant chemotherapy for Stage III colorectal cancer, suggesting that a choice between these 2 agents can be made on the basis of avoiding adverse events.

ABCA1, ABCG1, and ABCG4 are distributed to distinct membrane meso-domains and disturb detergent-resistant domains on the plasma membrane.

ATP-binding cassette A1 (ABCA1), ABCG1, and ABCG4 are lipid transporters that mediate the efflux of cholesterol from cells. To analyze the characteristics of these lipid transporters, we examined and compared their distributions and lipid efflux activity on the plasma membrane. The efflux of cholesterol mediated by ABCA1 and ABCG1, but not ABCG4, was affected by a reduction of cellular sphingomyelin levels. Detergent solubility and gradient density ultracentrifugation assays indicated that ABCA1, ABCG1, and ABCG4 were distributed to domains that were solubilized by Triton X-100 and Brij 96, resistant to Triton X-100 and Brij 96, and solubilized by Triton X-100 but resistant to Brij 96, respectively. Furthermore, ABCG1, but not ABCG4, was colocalized with flotillin-1 on the plasma membrane. The amounts of cholesterol extracted by methyl-ß-cyclodextrin were increased by ABCA1, ABCG1, or ABCG4, suggesting that cholesterol in non-raft domains was increased. Furthermore, ABCG1 and ABCG4 disturbed the localization of caveolin-1 to the detergent-resistant domains and the binding of cholera toxin subunit B to the plasma membrane. These results suggest that ABCA1, ABCG1, and ABCG4 are localized to distinct membrane meso-domains and disturb the meso-domain structures by reorganizing lipids on the plasma membrane; collectively, these observations may explain the different substrate profiles and lipid efflux roles of these transporters.