Keiko Hodohara

Comparison of imatinib, dasatinib, nilotinib and INNO-406 in imatinib-resistant cell lines

We compared the growth-inhibitory effects and inhibition profile of the SRC family kinases (SFKs) of imatinib, dasatinib, nilotinib and INNO-406. Dasatinib exhibited the strongest potency against BCR-ABL with little selectivity over SFKs. Nilotinib exhibited a weaker affinity than the other inhibitors, but was highly specific for ABL and may be useful for the treatment of P-glycoprotein overexpressing leukemic cells. INNO-406 had an intermediate affinity for BCR-ABL between that of dasatinib and nilotinib, and inhibited only SFKs LCK and LYN among SFKs. Both nilotinib and INNO-406 were potent inhibitors of the dasatinib-resistant T315A, F317L and F317V BCR-ABL mutations.

Glycosylation-Dependent Interactions of C-Type Lectin DC-SIGN with Colorectal Tumor-Associated Lewis Glycans Impair the Function and Differentiation of Monocyte-Derived Dendritic Cells

Dendritic cells (DCs) are APCs that play an essential role by bridging innate and adaptive immunity. DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is one of the major C-type lectins expressed on DCs and exhibits high affinity for nonsialylated Lewis (Le) glycans. Recently, we reported the characterization of oligosaccharide ligands expressed on SW1116, a typical human colorectal carcinoma recognized by mannan-binding protein, which is a serum C-type lectin and has similar carbohydrate-recognition specificities as DC-SIGN. These tumor-specific oligosaccharide ligands were shown to comprise clusters of tandem repeats of Lea/Leb epitopes. In this study, we show that DC-SIGN is involved in the interaction of DCs with SW1116 cells through the recognition of aberrantly glycosylated forms of Lea/Leb glycans on carcinoembryonic Ag (CEA) and CEA-related cell adhesion molecule 1 (CEACAM1). DC-SIGN ligands containing Lea/Leb glycans are also highly expressed on primary cancer colon epithelia but not on normal colon epithelia, and DC-SIGN is suggested to be involved in the association between DCs and colorectal cancer cells in situ by DC-SIGN recognizing these cancer-related Le glycan ligands. Furthermore, when monocyte-derived DCs (MoDCs) were cocultured with SW1116 cells, LPS-induced immunosuppressive cytokines such as IL-6 and IL-10 were increased. The effects were significantly suppressed by blocking Abs against DC-SIGN. Strikingly, LPS-induced MoDC maturation was inhibited by supernatants of cocultures with SW1116 cells. Our findings imply that colorectal carcinomas affecting DC function and differentiation through interactions between DC-SIGN and colorectal tumor-associated Le glycans may induce generalized failure of a host to mount an effective antitumor response.

Mechanism of NK cell activation induced by coculture with dendritic cells derived from peripheral blood monocytes.

Dendritic cells (DCs) have been regarded as one of the effective antigen‐presenting cells, but the relationship between DCs and lymphocytes, in particular natural killer (NK) cells, remains unclear. In this study, we evaluated how DCs interact with both lymphocytes and NK cells using a coculture system. The number of lymphocytes increased significantly when cocultured with DCs (1·8‐fold increase). In particular, the proliferation of NK cells was prominent. Furthermore, the coculture of DCs with lymphocytes induced a marked increase in IL‐12 and IFN‐γ secretion. When contact between the DCs and lymphocytes was prevented, the secretion of both IL‐12 and IFN‐γ was markedly reduced. IFN‐γ production was completely blocked by an anti‐IL‐12 antibody, indicating that IFN‐γ secretion was dependent on IL‐12 secretion. The stimulating effect of the DCs on the proliferation of the lymphocytes was partially suppressed by anti‐IL‐12 antibodies, and was completely attenuated when cellular contact was prevented. Furthermore, the NK cell proliferation induced by coculture with DCs was significantly blocked by the inhibition of the interaction of either CD40–CD40L or CD28–B7 molecule. The coculture with DCs enhanced NK activity by 40%, and this was partially suppressed by anti‐IL‐12 antibodies and was completely blocked by the inhibition of cell‐to‐cell contact. These results indicate that the activation of NK cells by DCs is partially mediated by IL‐12 secretion, and that direct contact between DCs and NK cells play a major role in this response.

Clostridium ramosum, an IgA Protease-Producing Species and Its Ecology in the Human Intestinal Tract

A bacterial strain isolated from feces of a patient with ulcerative colitis, which had been shown to produce a novel immunoglobulin A (IgA) protease (cleaving both the human IgA1 subclass and IgA2 subclass of A2m(1) allotype) extracellularly, was identified as Clostridium ramosum. By using a selective medium (proprion‐ate‐rifampicin‐gentamicin‐colimycin‐polymyxin medium) devised for C. ramosum, analysis of the population level of this organism was performed to determine its ecology in the human intestinal tract. C. ramosum was isolated in 20 of 25 fecal samples (80%) from patients with inflammatory bowel disease (I.B.D.) and in 112 of 135 samples (83%) from patients without I.B.D. (control group). C. ramosum was also isolated from 6 of 11 biopsy samples (55%) of the inflamed rectal mucosa from patients with ulcerative colitis and from five of 15 samples (33%) from the intact mucosa of the control group. The population levels of C. ramosum in most of the biopsy samples ranged from 2.3 to 5.0 log10 per gram. The IgA protease‐positive C. ramosum was found in only four of 135 fecal samples (3%) and one of 15 biopsy samples (6.7%) from the control group. These results indicate that IgA protease‐positive C. ramosum is not likely to play a role in the induction of I.B.D., unless the organism is first isolated from the patient with I.B.D.

Dendritic Cell-specific Intercellular Adhesion Molecule 3-grabbing Non-integrin (DC-SIGN) Recognizes a Novel Ligand, Mac-2-binding Protein, Characteristically Expressed on Human Colorectal Carcinomas

Dendritic cell (DC)-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) is a type II transmembrane C-type lectin expressed on DCs such as myeloid DCs and monocyte-derived DCs (MoDCs). Recently, we have reported that DC-SIGN interacts with carcinoembryonic antigen (CEA) expressed on colorectal carcinoma cells. CEA is one of the most widely used tumor markers for gastrointestinal cancers such as colorectal cancer. On the other hand, other groups have reported that the level of Mac-2-binding protein (Mac-2BP) increases in patients with pancreatic, breast, and lung cancers, virus infections such as human immunodeficiency virus and hepatitis C virus, and autoimmune diseases. Here, we first identified Mac-2BP expressed on several colorectal carcinoma cell lines as a novel DC-SIGN ligand through affinity chromatography and mass spectrometry. Interestingly, we found that DC-SIGN selectively recognizes Mac-2BP derived from some colorectal carcinomas but not from the other ones. Furthermore, we found that the α1-3,4-fucose moieties of Le glycans expressed on DC-SIGN-binding Mac-2BP were important for recognition. DC-SIGN-dependent cellular interactions between immature MoDCs and colorectal carcinoma cells significantly inhibited MoDC functional maturation, suggesting that Mac-2BP may provide a tolerogenic microenvironment for colorectal carcinoma cells through DC-SIGN-dependent recognition. Importantly, Mac-2BP was detected as a predominant DC-SIGN ligand expressed on some primary colorectal cancer tissues from certain parts of patients in comparison with CEA from other parts, suggesting that DC-SIGN-binding Mac-2BP bearing tumor-associated Le glycans may become a novel potential colorectal cancer biomarker for some patients instead of CEA.

Band 4.2 Shiga: 317 CGC → TGC in compound heterozygotes with 142 GCT → ACT results in band 4.2 deficiency and microspherocytosis

Summary. A novel compound heterozygous mutation of 317 CGC → TGC with 142 GCT → ACT in human red cell band 4.2 deficiency is described. A proband and his son suffered from compensated haemolysis with nearly complete deficiency of red cell band 4.2. Their red cell morphology exhibited microspherocytosis resembling classic hereditary spherocytosis (HS). Sodium dodecylsulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) showed band 4.2 to be nearly missing (< 1% of normal controls) with the presence of 74 kU and 72 kD isoforms in trace amounts. Other family members (daughters older and younger than the son) exhibited nearly normal amounts of 72 kD as a wild form of band 4.2 on SDS‐PAGE with the presence of the 74 kD isoform in a trace amount. The proband and his son demonstrated two compound heterozygous mutations in trans: i.e. nucleotide (nt) 949 CGC → TGC (codon 317 Arg → Cys) in exon 7 and nt 424 GCT → ACT (codon 142 Ala → Thr) in exon 3 of the band 4.2 gene. The two daughters demonstrated only the mutation of nt 949 CGC → TGC in exon 7 in heterozygous states, but no 142 mutation. Therefore the proband and his son were compound heterozygotes of these two mutations in trans. It is interesting to note that the 74 kD isoform of band 4.2 protein existed in a trace amount in the two daughters in spite of the absence of the 142 Ala → Thr mutation. In addition, even in the presence of the 142 mutation in one allele in the proband and his son, their red cell morphology demonstrated classic HS with microspherocytosis, although a homozygous state of the 142 mutation known as the Nippon type of band 4.2 deficiency exhibits ovalostomato‐cytosis.

Acute lupus peritonitis successfully treated with steroid pulse therapy.

A 21-year-old man with systemic lupus erythematosus (SLE) who developed acute lupus peritonitis is described. Acute lupus peritonitis appeared during generalized lupus flare, with nausea, vomiting, frequent diarrhea, and abdominal tenderness with rebound and guarding. The patient was afebrile and had decreased bowel sounds. Abdominal ultrasonography and computed tomography revealed marked thickening of the gastric, duodenal, and jejunal walls, massive intraluminal fluid collection, and increasing ascites. Gastrointestinal endoscopy showed edematous mucosa with multiple erosions of the stomach and duodenum. The ascitic fluid was remarkable for low complement levels and elevated anti-DNA antibody. These manifestations of acute lupus peritonitis resolved after steroid pulse therapy with methylprednisolone. We should consider acute lupus peritonitis in a patient with SLE when abdominal symptoms are severe. Experience with our patient indicates that steroid pulse therapy is effective for this rare but severe manifestation of SLE.

A Case of Interstitial Pneumonitis Associated with Natural α-lnterferon Therapy for Myelofibrosis

A 55-year-old man with myelofibrosis was treated with natural alpha-interferon with a good hematologic response. Initially, he had anemia, leukocytosis, thrombocytosis and hepatospleomegaly. A bone marrow biopsy showed replacement with fibrosis with an increase in megakaryocytes. Natural alpha-interferon (alpha-IFN) was started at a dose of 3 x 10(6) units/day. The leukocyte and platelet counts gradually normalized, and the liver and spleen decreased in size. However, the patient complained of a dry cough and dyspnea on the 61st treatment day, when the accumulated dose of alpha-IFN treatment had reached 1.8 x 10(8) units. He subsequently developed acute respiratory failure (PaO2 < 60 mm Hg) with bilateral lung infiltrations, suggesting the occurrence of interstitial pneumonitis associated with alpha-interferon therapy. Immediately, the alpha-interferon was discontinued and high-dose methylprednisolone (1.5 g/day) was administered for 3 days. This treatment was followed by oral prednisone therapy. Steroid therapy brought about gradual improvement as suggested by a repeat radiograph. Since high levels of fibrogenic cytokines, such as PDGF and TGF-beta, have been reported in patients with myelofibrosis, it is necessary to pay attention to interstitial pneumonia as a complication in alpha-IFN therapy for myelofibrosis.

Small intestinal perforation due to cytomegalovirus infection in patients with non-Hodgkin's lymphoma

We describe two patients with non-Hodgkins lymphoma (NHL) who suffered cytomegalovirus (CMV)-related small intestinal perforations during the course of chemotherapy. Surgical specimens from both patients revealed histologic evidence of occlusive vasculitis and tissue destruction caused by CMV-affected cells in the submucosa and muscular walls, that may have played an important role in the pathogenesis of these perforations. Although such intestinal perforations are rare complications in NHL patients, CMV infection should be recognized as a primary etiological factor in acute abdominal crises when treating NHL patients with pharmaceutical agents including steroids. Emergency surgery and the anti-CMV agent, ganciclovir, would improve the prognoses of such patients.

Haematopoietic action of flt3 ligand on cord blood‐derived CD34‐positive cells expressing different levels of flt3 or c‐kit tyrosine kinase receptor: comparison with stem cell factor

We compared the effect of human flt3 ligand (FL) and stem cell factor (SCF) on cord blood (CB)‐derived CD34+ cells expressing different levels of flt3 or c‐kit tyrosine kinase (TK) receptor in clonal cell culture. The c‐kit receptor was expressed by 58.5±16.7% of CB CD34+ cells (n = 19), in which c‐kithigh, c‐kitlow and c‐kit‐ cell populations could be identified. In contrast, the flt3 receptor (FR) was weakly expressed on 58.6±8.3% (n = 9) of CB CD34+ cells. FL+erythropoietin (Epo) failed to support erythroid burst (BFU–E) formation by any subpopulation of CD34+ cells. However, SCF+Epo supported BFU–E and erythrocyte‐containing mixed (CFU–mix) colony formation from all subpopulations. Interestingly, FL markedly augmented CFU–mix colony formation supported by interleukin (IL)‐ 3+Epo when CD34+c‐kitlow or CD34+FR+ cells were used as the target. On the other hand, SCF significantly enhanced CFU‐mix colony formation supported by IL‐3+Epo when CD34+c‐kithigh or low and CD34+FR+ cells were used. The replating potential of CFU–mix supported by IL‐3 + Epo + FL was greater when CD34+c‐kitlow or CD34+FR+ cells were used. When the CD34+c‐kitlow cells were used, the number of lineages expressed in secondary cultures of CFU–mix colonies derived from primary cultures containing IL‐3 + Epo+FL or SCF was significantly larger than when the primary cultures contained IL‐3+Epo. Furthermore, the number of long‐term culture‐initiating cells found in CD34+FR+ cells was larger than that in FR‐ cells. CB‐derived CD34+c‐kitlow cells represent a less mature population than c‐kithigh cells, as reported previously. Therefore, these results indicate that both FL and SCF can act on primitive multipotential progenitors. However, it is still uncertain whether CB‐derived CD34+FR+ cells are less mature than CD34+FR‐ cells.